The Device Pt. 01

All characters over 18.

########## Discovery ##########

The box in front of Mark came with a note inside - in a language he couldn't read - and a device that looked like a watch - unlike any he had seen before. The box was put inside his room, laid on top of his sloppily made bed, in plain-enough view that he had no choice but to notice it when he came home from his summer job that afternoon.

He took a swift look around the room when he had first discovered it and called out through his open door "Mom, Sarah, Danny, Dad?"

There was no response, and typically wouldn't be at this time of day anyways. Mark worked the opening shift at the gym, and was normally waking up and coming back home before the rest of the family was eating lunch.

"My birthday was last month, this must be a prank gift then." He wondered aloud. Mark scanned the room for other signs of entry, hidden cameras that Danny or Sarah might've left. He figured if he opened the package and glitter sprang out, that would be a prank from Danny. If an embarrassing picture was inside, it was Sarah.

Instead, just the watch, with a strap wrapped around a small leather-like cushion inlaid into the bottom of the box, and the note, written on a relatively normal piece of parchment next to the watch.

The watch wasn't the first strange thing about the present, that was the box itself. When he picked it up off the bed it had at first felt heavy for a short moment, then light enough he would have no problem lifting it. It shot a small bolt of what felt like electricity through his arms when he grasped it, then stopped at the same time the box seemingly changed weights. The box also had no discernible opening mechanism. No buttons, no clear lid. After a moment of wondering how his siblings planned on him opening the strange contraption, it responded by cracking open the top of the box, and further opening ninety degrees to reveal its contents inside.

It was a strange prank. Mark wasn't sure what the end game of a watch and an alien note was supposed to be as far as pranks go, but he figured if the device didn't blow up on him, it had to be something complicated. Maybe this was some old antique thing his siblings would convince him to wear to school to embarrass him. Or maybe it was just a gift. Mark wouldn't put it past Danny to come up with some fake language and elaborate box to gift him a weird watch he thought was cool.

Mark picked the note out of the box, determined he wasn't going to make any sense of it yet, and decided to pick the watch up instead. What probably counted as the face was completely black. It was most likely digital, but it hadn't come online yet. Around the face there were 8 inlets, places where it looked like diamonds would be set. Right now the inlets were empty, but from the looks it a larger carat diamond would fit perfectly. There were no buttons or knobs along the side to try and use to turn the watch on, and the strap was larger, and it looked like it would fit a must larger wrist than Mark's.

Whatever this "watch" was, it was made out of a smooth metal, almost too smooth. When you looked at the watch face and strap you couldn't tell where one started and the other stopped, and there was no clear housing for the "face" of the thing. This clearly wasn't an antique, and whoever made it could've charged a pretty penny for it. Mark couldn't make sense out of either of his siblings wasting money on whatever kind of stupid prank this must be.

Tentatively, Mark figured there was only one real way to figure out where the whole setup would lead. "Hope your cameras are still recording!"

He slipped on the watch to his left wrist and felt the same bolt of electricity as before shoot from his left arm nearly all the way to the lower part of his neck. The shock took his eyes off the watch long enough that when he looked back the band had shrunk and conformed to his wrist. What was once a strap that would've fit a man twice his size had come down to a more reasonable size and snug fit. The watch face had somehow also shrunk to a comfortable form, and the inlets looked like they would accommodate much more affordably sized gems.

"I don't know what sort of trick watch this is, but I'm going to kick the ass of whoever put it here!" Mark yelled to the empty house. Truth be told, he was more shocked by the unexplainable properties of the watch than angry at the low level shock it had given him, but had no more doubts about the nature of the prank. Put watch on, get shocked, get posted online for being dumb enough to have worn a mysterious watch planted by his siblings.

Time to get the watch off. Only that, he found the watch refused to budge.

The watch was a little more than snug on his wrist, it was absolutely tight, and any attempt to find a place you could undo the strap or free your wrist failed. "Ok so... how do I get the watch off now?" Mark told the imaginary cameras he figured were watching the scene. "I get it, I'm stupid, it's a fun trick watch, but I don't want to be shocked again!" He tried to get under the strap to see if he could loosen the strap enough to get the watch off his arm, but it almost seemed as if the entire thing was fused completely to him.

Mark stopped for a moment and stared at the new, seemingly permanent, resident on his wrist. When he finally accepted that it might be there to stay, the bezel-less face came alive.

It looked like an LED screen, but looked like it had far more definition than any smart watch he had ever seen. Whatever information it was displaying was flying at a mile a minute, and even if he could make sense of the information, it was going far too fast for him to make any sense out of it. What he could make sense out of was a small ball of bright blue electricity that was now pulsing out of one of the eight small inlets on the watch face. A foreign voice deep inside Mark, one he hardly knew was there, told him to reach out and touch the inlet, to feel the electricity. As he did, the same feeling of shock and electricity started at his finger and blazed through his body. It reached out further than before, from his arm where it started, to his neck and to the top of his head through his hair, out again through his waist and to his legs. It reached out and bathed his body in new sensation.

The feeling had lasted for a minute and felt as if it was stretching and controlling Mark's body. The feeling was almost too much for Mark to handle, his head started to throb with pain, his vision becoming dark and distorted. The pain brought his vision crashing inward as he fought his way to the mirror in the corner of the bedroom.

What Mark saw must've been a hallucination. Through his darkening tunnel of vision, he could confirm that his body was indeed changing as it felt. He had grown nearly a foot in height, his skin grey and dark. He began to feel them new sensations throughout his body as he shakily removed his shirt and begun to spring two new arms from below where the others had been.

His muscles were larger, almost dramatically so from what they had been before. He looked at his face, and saw something unfamiliar, if not at least humanoid staring back at him.

His muscles weak from exhaustion, the electricity beginning to fade somewhat from his body, Mark felt darkness creeping closer and closer from the edges of his vision. He began to walk, then shuffle, falling to his knees and inching towards his bed. As he managed to hoist himself into a sitting position on his bed, he figured he'd take second look down onto his body to see if he could confirm what the mirror had told him, and he looked down onto two large alien feet planting themselves on his bedroom floor.

His last thought, and last visual confirmation that something had changed was far more unexpected than any of the previous indications of strangeness. Mark removed his shorts, and saw not one, but two long alien penises where there only ever should have been one.

########## The Vision ##########

"So you swear, whatever happens, you won't scream, you won't leave the room, you won't... freak out or anything, right?"

"If this is some stupid fucking prank I'm leaving."

"Sarah I swear to you this isn't a prank. I'm going to do something with this watch and I swear you've never seen anything like it in your life."

"If you hit me with the watch or it sprays something I'm calling mom and dad immediately. Me screaming will be the least of your problems."

Sarah sat, now slightly uncomfortably, on the edge of Mark's bed. It was barely mid-day and she had just got home from her morning classes at the community college. Dressed in a crop top and her workout leggings, she was every bit the community college girl-next-door, only she was held captive in her brother's room as part of what she could only assume was an extension of their long forgotten sibling prank wars.

Whatever Mark was playing at was annoying her. She had planned to hit the gym right after coming home from school so she could beat the crowds, and planned a full day of homework after that. There was an amazing rave at the dunes this weekend that she had an outfit picked out for. There wasn't anything that was going to keep her from that festival and her friends.

"I know, I know this sounds like I'm trying to fuck with you, but I swear this is the real thing. I thought you or Danny was fucking with me when I found this watch in my room." Mark showed her the watch again, rotated his wrist to show the strap, made a show of pulling at it to show how the watch stayed firm against his wrist.

"Ok... so it's a weird watch. What is it exactly that you're going to show me that's going to ~shock me~ or ~blow my mind~?" She asked and mocked his exasperation.

"Well, maybe it's just best if I showed you. Remember - whatever you do - don't freak out, please."

With his last warning, Mark reached again for the spark laid inside the first spot on the watch and felt the same electricity begin to course through him. Even before his finger made contact he could feel the beginnings of the transformation hit his body, felt his skin turn and arms grow in size and number. This transformation was his fifth into the body, and the first in front of anybody but himself. He begun to feel the growth in height and familiar shock of the transformation wash through his body.

Sarah would've been in shock herself if it wasn't for effects of the watch that started to pour over her own body. Unbeknownst to her brother, the watch had a changing effect on her too.

It was like a shock, not as intense as the shock that had hit Mark, but a shock none-the-less. For a moment she was briefly aware of her brother's body beginning to morph into something non-human, but as she did she also felt a wave of ecstasy beginning to course from her chest out to the rest of her body. The anxiety of the unknown, the fear of something different. Unfamiliar (and even some exciting) emotions coursed through her and caused her arms and legs to tingle.

A voice inside her spoke to her, in a language she couldn't understand. Sarah's eyes darted to the back of her head. Her mind flashed with moments that felt like she had experienced them before:

A four-armed body grabbing both her arms and legs at once, throwing her onto the alien body's shoulder, standing upright, then throwing her down on a bed. Her hair and head being pulled from behind by the same figure, still managing to land a controlling hand on her ass, her thigh, and her ankles, all at once. She could feel not one, but two large members pushing and working to penetrate her workout pants.

A body unlike any she could have imagined, using countless arms and appendages to control and restrict her. Cold and then hot as it strangled her legs, her mid-section, wrapping slowly and deliberately around her neck and controlling her breathing. She felt herself choking on an imaginary arm (or appendage?). Spit forming on the seal she made around the surface of the appendage with her lips.

She saw a short man-like alien standing before her as she was on her back, a penis in front of her that would've ended discussion in any locker room. As the alien man creeped forward and set his pelvis on the back of her legs, the specimen of man-hood was laid on her pubic hair and came down nearly between her breasts. She looked towards the head as it was looking at her and almost could've sworn the thing would've winked if it was able to.

Then a beast, like a werewolf. She saw fur and muscle and fear creeped over her. In a shadowy room the beast seemed to take a large inhale through its nose and turned its head towards her. She shrunk back, but wasn't quick enough to move and the beast took her, ripping through her clothing and pinning her to the wall.

Just when she thought the fear wouldn't subside, she was standing instead next to a massive alien man, the size of which she wasn't sure would manage to fit inside a normal house. A small cloth managed to hide its manhood, and though she felt safe, the giant reached out with a hand and... offered it to her.

Then she looked again and noticed that she was with her brother Danny, only he wasn't Danny. It was him, but how she imagined Danny might look if he were Daniella instead. The new Daniel was how she might imagine a man would've drawn an "ideal" woman, if that ideal woman was thick and thin in a way that could only be described as lusty, if not outright non-proportional. An alien watched over the scene, and when she thought this vision was complete, realized that her own body had changed to resemble her own ideal image of a man.

When her mind came back from the shock of seeing her own transformation, she was now in the embrace of a tall woman, an amazonian, alien, woman. She felt waves of love as the beautiful woman carried her through the door of her own house, into the same room she remembered being in before the visions, and carefully laid her down on Mark's bed. The woman was naked, something over 6 feet tall, with soft breasts that would've made her old high school class jealous. She had arms that looked like they could've carried a person three times her size. As Sarah's mind went down the imaginary alien woman's body, she saw a flat, toned stomach, and the beginning of a large, thick penis that ended in a perfectly shaped head. The woman grabbed Sarah's cheek, kissed her gently, and laid down on top of her on her brother's bed. She felt the eyes of others in the room watching her, but still only felt love and belonging. The alien woman wasted no time in penetrating her partner. Sarah felt the alien woman's body slip neatly into hers, and went numb as pleasure and ecstasy washed over her again. Her vision again went dark as she slipped further and further into darkness and finally, sleep.

########## Sarah Asleep ##########

"Fuck Sarah you have got to wake up someone's gonna come home any minute."

The transformation for Mark had gone well, but it was nearly five hours later and Sarah was still asleep on his bed.

Mark paced around the room and planned aloud. "Ok, I'll just tell them that we were talking when you got back from class, I stepped out of the room and you must've fallen down for a nap without thinking about it. That's not that crazy, I don't know why anyone would freak over that."

Sarah has curled into a ball on his bed and was snoozing comfortably since Mark had shown her the watch and his transformation earlier in the AM. The transformation had actually gone wonderfully for him, even at just his fifth time using the watch, the transformations had begun to feel more comfortable. He had even begun to acclimate to his new body, and had used the four arms to accomplish some chores after his initial scare from his sister passing out had subsided.

Now Mark had sat at his desk, in his original human body, and began to ponder the true nature of his newfound gift. Was he supposed to use this body for some sort of... super hero style work? He lived in perhaps the most disadvantageous place for such work, in a sleepy suburb outside of Denver, a relatively non-violent city. Did the beings who sent this watch know that it would take a rather insurmountable amount of work for a kid in his gap year after high school to even figure out where the crime really was in this city? Wouldn't it make more sense to send this kind of ability to someone fighting organized crime? Was he supposed to go out and find some injustice that could only be fixed by a freakishly buff man with four arms?

And the most important question of all, if he was supposed to do something heroic with this body, why the fuck did it come with two penises? Would it be weird if it didn't come with a core biological component?

With that thought, Mark heard the door close and jumped out of his chair, rushing to the door to his room.

"Anyone home? Sarah, Mark?" He heard his mother call from the doorway.

"Yes mom! I'm home and Sarah is too, she's just asleep!"

His mother walked into the living room and Mark quickly closed his bedroom door. "Sarah got home and I think she wanted to take a long nap before going out tonight. I think she was so tired that she passed out on my bed while we were sleeping."

"That sounds fine honey, do you want me to wake her up so she can go to her own room?" His mother Lianna inquired.

"No, no. I think she would just be able to sleep for a bit. It seems like the least I can do to let her rest if she was that tired." Mark was overcompensating sure, but from his mom's perspective there really shouldn't be anything wrong there. After all, she had no real clue of any of the events from earlier that day.

"Well that's fine, very kind of you I guess. Anyways, your father and I were thinking tacos for dinner tonight. Think you'd be down to help your mom with the tortillas right? You know I could always use a few extra hands when I'm getting things ready!"

"Absolutely mom."

Lianna truly had no clue how many hands she could really have at her disposal, if she truly knew.

Later that night, while Mark, Danny, and their parents enjoyed a nice home cooked meal, Sarah quietly and quickly swept from Mark's room into her own, to enjoy a night to rest and gather her thoughts.

########## The Examination ##########

"I want you to do what you did again."

Sarah sat again on the same spot of his bed, the same time as she came home the day before. Mark sat opposite in his chair by his computer.

"Are you sure that you want to go through with that again? I thought you almost died the first time I showed you. Are you sure you can handle it? Maybe I could just go through with it and show you a video later?" Mark managed to continue to offer solutions before Sarah could reply. "I swear I'm not trying to drag you into this either if you don't want to be, I just don't know who else I could trust with something as weird as this. I'm really not trying to go to one of the guys who might blab, or really go out of the house at all with this thing. I'm still praying no one at work or here at home starts to ask questions about this watch."

Sarah had slept nearly sixteen hours the night before after the visions had hit her. She barely managed to wake for her alarm for class, made it through all courses that day without a single thought for any of the material.

She wasn't sure if she truly wanted this. To go down this rabbit-hole of her brother's watch, of her lewd, alien visions. And who was she supposed to talk to about any of this? Sarah couldn't remember the last time she had been in any difficult situation without debriefing first with her friends. She had realized quickly after waking up that alien sex visions and a brother with an alien watch might not be the thing you would want friends gossiping behind your back about.

Whatever trepidations, she knew there was a voice deep inside her telling that there was only one true path forward, one that would reveal more about the visions.

"I'm sure." She reached out and touched Mark's leg reassuringly. That same electric feeling as the day before shot through her fingers and faded weakly at her wrist. "I don't want you going through something like this alone, and I'm sure two heads are better than figuring out what this is all about than one."

Mark looked down warily at his watch, took his right index finger and pressed down on the inlet filled with electricity. His body began to grow in the ways that he was now familiar with.

Sarah watched as Mark's body began to glow with light and took on a new form. His skin became grey, his arms and muscles throughout his body began to grow throughout his body, rippling and bulking in ways she was sure he could only dream of in real life. His chest began to grow, his neck became thicker, his legs became like tree trunks in size, and his feet expanded like those of a basketball players. He towered over a foot from where he was before, and from under his arms two more, equally as thick as the standard two, sprouted. When the transformation was complete, Mark stood above her in his new body, grey skin covered sensibly in certain portions by a thin and futuristic black suit.

His head also changed. Slick ellipsoid eyes, black with a hint of grey pupils in the center. Even for an alien, she supposed whatever it was looked confident, regal almost. Like it would have an air of superiority about it if the body had came with any personality of it's own.

"Isn't this insane? I have four arms Sarah. Four. Arms. And do you see these legs? The guys from the gym would have to work for years to look like this. They'd have to take tren at the least. And the strength, you have go to see this, look."

Mark moved to the bed, near where Sarah was sitting and lifted the side of the bed. From under, he grabbed a hundred-pound dumbbell he must've stolen from the gym. He set the bed down again and tossed the weight from one hand to another, and then another.

"This weight doesn't feel light like a feather, but it certainly isn't heavy either. I don't think I could touch this thing except for a bench press in my regular body, if I worked at it. It feels like a 20, or maybe a 25 now? I wonder how a bench press even would work in this body, would all arms workout the same section of my chest? I wonder if I have more sections of the chest, I sort of have a separate shoulder for each arm, but how would I even go about working them..."

Sarah rose silently from the bed and approached Mark's four-armed alien form as he was using the mirror to examine himself. She could feel the electricity start to saturate the air now as she got closer to his new body, she figured there would've been an arc connecting them if this was any form of real electricity. Mark must've felt her presence and turned around quickly to stare down at the girl.

"... Sarah?"

She put a hand out to touch his bicep and expected the shock to ripple up her forearm again, but instead she felt a low heat emanate from her hand that rapidly filled her chest and her thighs. She didn't say a word to Mark as she inspected both his upper and lower right biceps. They were made of steel, and each grasp left a small place grey spot that quickly regained its color. His shoulders were cut between each section, and his forearms were possibly ripped straight from the pages of the annual Denver fireman's calendar.

The new body's hands were also wildly impressive. She grabbed one of his right forearms and brought her hand to his. Despite standing heads above her, Mark complied with her unspoken direction. Sarah compared the size of each, then held his forearm tight to see how the sinew under the skin moved when the arm was flexed and rotated.

Sarah didn't believe in the ideal male body, but the heat in space between her thighs and deep within her chest told her that two sets of amazing arms on one body might be pretty close to ideal.

"Move... over here." She pulled Marks arms in the direction of the bed, and though she wouldn't have been able to do much to actually move him, he wordlessly complied and moved to the bed. "Now sit down."

Mark was entranced by the touch of his sister. Although he wasn't affected by the same heat as his sister, he certainly felt the same level of horny as he would've in any other situation, only this time in a peak-physique alien body.

Sarah was lost in thought about her brother's alien form. What the arms could do to a woman. The size of his fingers. Sarah knew she was fully conscious this time, but wasn't sure if there was somebody else inside her giving her help with directions. If she had been in absolute, full control, would she be thinking about the visions of what her alien brother could really do to her with this alien form?

With Mark sat on the bed, Sarah leaned in and looked more closely at his head, his neck, his chest, his back. Every square inch was laid with muscle. She was practically straddling him now her hands running down his back to examine his new shoulder blades. When she got tired of that her leg swung gently over his so she was just above his thighs and began running her hands over his chest, touching the aliens jaw bones, and of course, his arms once again.

Sarah leaned in closely and went to take a closer look at his facial features when her leg brushed against his shorts. She pulled it back for a half second, then put it back. Her thighs lit on fire and she could feel wetness in her shorts, and through his shorts she could feel a at least one of the two alien penises that she had seen in her visions.

"Sarah I think your leg might be touching me, you might want to back up." Mark protested, weakly. Truth be told he was doing everything he could to try and keep blood from gorging both his new members. He could feel himself getting hard, causing his suit bottoms to tighten and restrict further, causing the pressure to hamper his efforts to remain flaccid.

Sarah stopped moving her arms and grabbed both his shoulders staring him dead in the eyes. With perhaps the hottest voice Mark had ever heard her produce, she asked: "Do you think we should find out how every part of this body performs?"

Without waiting for a response she dropped to her knees on the carpet in front of the bed and gave a ruthless tug on Marks alien shorts. They were tight, but unlike the watch they gave way when she began to pull harder. Mark was in awe of the state of his sister in front of him and had forgotten all about his battle to keep himself from getting hard. Sarah gave another tug at the shorts. They were getting stopped by his erection, but she managed a final tug and got the shorts over the hump of his manhood and over to his knees.

Sarah was stunned when not one, but both of two cocks she had imagined sprang forward and laid themselves before her.

They were more than she ever could have dreamed. Thick in a way that wouldn't break you, long enough that you could reach all the correct spots with extra to spare. The heads of both were a light gray, visible veins running down the side. A ridge with pronounced bumps ran along the top of both that was clearly alien in design. She reached out a finger and gently ran the tip over the ridge, thinking about how it would feel when thrust inside of her.

Then, unceremoniously she took the head of the topmost penis in her palm and lifted it to see the whole of the other. Mark was clearly a slave to her touch and his new body. His first dick (the upper one) became as hard as a rock and was pulling itself from his sister's grip. She looked back from the second and saw the underside of the shaft. Smooth, hairless to the touch. She was biting her lip hard enough that it became sore, she realized she must've been making a ridiculous face. She decided that she wanted to be back in full control, but that didn't necessarily mean stopping.

"I don't know what the fuck has me so bothered for this new body, but I've decided that I need do my duty as the world's first xenobiologist and catalogue whatever this new species is. Now stand back up and let me take off these ridiculous shorts."

Mark was indeed a slave to her whim and rose from the bed on her command. She stood to help him get off the tight shorts from his knees and decided to run a hand over his legs.

"How big do you figure each one of these are anyways? I don't know if I'd believe you if you're gonna tell me you haven't got hard and measured yet."

"Each is nine and half inches." Mark shuddered. She was touching him everywhere but his dick now, but he was still jelly to her touch.

"Well I don't know if I fully trust your judgement. I think a good biologist would check those measurements, don't you little brother?"

She stood by his legs and held her forearm up to his first dick, then his second. "I guess that could be nine, let me go grab a measuring tape." She bounded off to her room, leaving the door open on her way. It was midday, but if Danny or their mom decided to come home, they really did have a problem on their hands. Sarah at least still had her shirt and her top on, but Mark would probably struggle to explain a naked alien with four arms and two penises.

When she got back and closed the door she had a small measuring tape in her hands, probably one dad had used to work on small projects around the house. She stood in front of Mark, incredibly close, and looked up at him. "Final guesses, exactly nine or less?"

"They're both nine. I swear."

With that, she grabbed at the shaft of his upper penis, then managed to grab the head and the measuring tape at the same time. She pulled the tape out and extended it to the base where his pubic hair would've been.

"So that measures nine, well done little brother, you aren't entirely stupid after all." She threw him a wink that would've made a statue melt. As she took away her hand from the head she gave it a look and held it up for him to see. "Precum huh? Guess that's a good sign of bodily function."

Sarah wiped her newly sticky hand on his stomach and grabbed the other, lower head. She measured the same way, but this time to the base of where the penises met in the middle.

"Now that... is not nine. That is..." she dropped down to her knees to measure closer. "Is eight and a half! You fucked up measuring your alien penis, idiot."

"Wait a minute, do you actually..." She put the measuring tape down and then used her left hand to lift up both dicks. With her right hand she gently pinched his balls underneath and turned them this way, then that way, then she cupped them fully, nearly shocking her with her cold palm. Then she exclaimed: "You didn't tell me you have three balls!"

She was close enough he could feel her breath from every statement on his dicks.

"All this time we've been focused on these dicks, and we didn't realize you had these" she gave them a healthy squeeze "fat massive balls." She was nearly completely underneath him now, admiring his new manhood.

Even in this lewd scenario she managed to find a way to tease him.

Just when he thought they would go further, she stood up and proclaimed "now that we've measured you, I think it's only ok that we measure me too. Use the measuring tape, I've been working out lately and I want to see what my hips and waist are at."

Mark would've complied if she had asked him to jump off a bridge, much less take part in this sexy scenario with her. Still nude from the waist down, he scooped the tape measure with one hand and moved over to comply.

"Oh, we should probably remove my shorts to make sure the measurement is as accurate as possible right?"

Mark needed no motivation, with his lower two hands he carefully peeled his sister's shorts off her frame, careful to bend down a little towards the end because of his height. She was wearing a thin, black thong underneath that left little to the imagination. When he went for that too she grabbed one of his wrists.

"You can leave that for now. Just the measurement bud."

Still, Mark had an amazing view. His sister worked out, and it showed. Every simple and little imperfection in her skin showed in this light. She had perfect hips and smooth, creamy skin. He dropped to a knee so he was at a manageable height to measure her hips first. He took a hand, put the tape measure around her, then grabbed the tape from the other side.

"33 inches."

"Ok, now my waist."

Mark began to move the tape measure when he lost his balance, used one hand to steady himself on the floor and used the other to grab his sister, make sure she wasn't moved by him. It was a large, grey hand on her bare hip right by her ass.

"Oh, Mark."

Mark could see now that the little slip of fabric between Sarah's ass was nearly soaked through. He was practically salivating and struggling to control his new arms as he wrapped the tape measure across her waist. He kept the large grey hand on her side, place another on her calf to help keep her steady.

"24. Wow."

"I think we should just progress a little to the practical part of the biological examination now." Sarah spoke as she turned and brushed his hands off of her. She pushed his body back towards the bed. He worked to pedal backwards and made sure to keep a hand out for the bed, lest he crush it on the way back. When he found it he took a careful seat down, Sarah was now straddling his legs again, and gave a forceful push to him to force his back down onto the bed, his head bumping the wall back wall and keeping his view of her upright.

Mark would never forget the look of his sister then. Her hair was messy, down covering her face. She still wore her crop top she had worn to school, but was sporting just her thong below the waist now. While Mark knew that he was in control of his new body, he wondered if anything different had possessed her. He had never seen this side of her before, presumably reserved for her community college coeds. And likely then, probably never at this ferocity.

"Do you think it's ok if I use my mouth on your new body Mark?" She asked. His dicks practically jumped at the question.

"I'm.. I'm not sure if we should."

She took a hand off his leg and confidently grabbed the highest of his two cocks, poised it upwards at the ceiling (not that it needed much help) and stuck her tongue out. She leaned forward, put her head fully between the two monsters, and gave it a lick that lasted from the base where the two joined to just under the head, stopping where the skin stretched and met between the head and shaft.

She licked her lips once and added: "I think we should, actually."

Mark was speechless.

Sarah wasn't going back to whatever she had been before. Whatever relationship she had with her little brother was over, and she relished in the new possibilities his watch and form would give them. She didn't much care if he chose to fight crime, become a hero, nothing. She only cared that she was the first to enjoy a body that seemed like it had come from her wildest dreams.

She managed to gather all the spit she could muster and spit onto the grey head of the first cock. "I think the next order of business then is to see how climax works, right little brother?" She knew she needed more than to experience just oral with this body, but she was too excited in the current situation to rush things. Plus, what's wrong with working up to a hotter plane?

Sarah used her hand to work the spit along the head, then the shaft. She leaned in again and got to the base of the shaft. She managed to look across the bed to her brother's alien eyes and gave the underside of shaft a healthy kiss. Then higher. Then again higher. She reach the spot right beneath the head and gave a kiss like she wanted to work a hickey into the skin, then in one move placed her lips on the head of the first penis, right at the hole and give it a kiss like you might put on the cheek of your boyfriend after a long date.

"Oh fuck Sarah." Mark let out before letting his eyes close. She took one last look at his face and took the head of the penis whole in her mouth. It took everything in Mark not to release fully then and there.

When he opened his eyes he looked to see his uppermost penis, only a few inches down, enveloped by his sister's mouth and lips as she worked heartily on his new body's penis. Her hair was obstructing some of the view. This wasn't his first time receiving head, but this could possibly be the best blowjob he would ever receive.

"Dude you're.. really good... fuck, really good at that."

Sarah opened her eyes and stared right back at her brother staring at her. She continued to work on his cock, using her tongue to help give the head pressure when her mouth worked further and further down the shaft, giving the absolute tip of his penis a small tongue lashing when she got to her furthest depth. She gave another cold look and stared into his eyes as she tried to speak: "issft itzche fwrend gwettin wonewy?"

Marks head was cloudy, she wasn't even sure if he would be able to register anything she attempted to say with a mouthful of an alien cock.

She let her head come back to the tip, maintained eye contact, and brought her cheeks into something like a duck face pose you would've seen in her old photos. She suctioned her cheeks hard, letting her lips rip off the face of the head as she came all the way off, creating a small popping sound as she finally freed her face from the monster.

"I said, do you think it's friend is getting lonely?"

"What are you talking ab..." Mark's voice trailed off as Sarah spit again on the head of the lower penis, lifting the first out of its way.

"What a shame I only have one mouth to help you acclimate to this new body huh?" She gave the shaft a long stroke, some of the spit clung to her hand as she ran it down to the base. "I think we can solve that problem later, but for now..."

He watched as his 20 year old sister, still the upper-most penis in hand, took the head of his lower penis in her mouth. She spent no time in working her lips past the mushroom ridge of his penis and onto the ridges of the shaft below, wasting no energy in involving her tongue and letting it smooth the underside of the shaft. She had managed to get her head nearly halfway down the shaft before he took a deep breath through her nostrils. Whatever new heat and sensation his form had inadvertently given her, it had miraculously given her a new mastery over her gag-reflex as well.

She had never had something like this in her mouth before, and Mark could tell she struggled with the bumps and lines that dominated the upper-side of this new dicks.

Sarah locked eyes with her brother. There were small tears streaming now, no mascara from the day to ruin. She let go of the first penis and brought both her hands onto his waist, letting the shaft come down on the top of her hair, and steadying her legs.

Her brother's view now obstructed from hers, she now let out one more gag, her eyes still filled with tears she closed them and let in one last hearty piece of breath through her nose before grabbing his sides tight and bringing her mouth down further onto his penis. She managed to reach the point where both dicks met, tears now freely rolling down her face.

Mark had tried to control himself, to keep him from reading in this new body. When his sister finally reached the bottom and had taken his new form whole, he finally released.

Sarah felt him twitch and knew what she had done. The whole of the cock enveloped inside her throat pulsed once, then twice, then a third time as it filled her throat. Alien sperm invaded her stomach. Mark's eyes rolled into the back of his head, but if they hadn't they would been treated to the show of his second cock pulsing the same and releasing a stream of thick white alien cum first onto his sisters hair, then once more a thicker rope onto her neck and back, striking the highest point of the top. On the third pulse he shot even further down her back, coating the back of her black crop top and making its way down just before her thong on the small of her back.

Sarah's lips glided with wetness from the shaft and she grabbed the dick to help guide it out of her mouth. When she finally freed it the top-most dick laid limp to the side, allowing Mark a view he was never to forget.

There, his sister of 20 years, holding a thick, grey, alien cock only inches from her mouth. Still struggling to catch her breath, a string of saliva and cum stretched from her mouth to the head of the coated penis, connecting them still. Her face was beet red from the "biological research" effort. On and above her lips, around her chin was the same mixture, thick and covering her skin in the liquid from his new body. He sat upright in the bed to get a better view.

In her hair, on her back. She was completely covered in cum. It was an awesome sight, Mark doubted it would've mattered, but it made his twin cocks hard again in excitement. He hadn't seen anything like this in porn, and even then nothing could have come close.

She opened her eyes and looked up to the strange eyes as she could tell Mark was reveling in what she had done. He braced and arm behind himself and came closer to her head with his, reaching two of his meaty hands to her head, one to her thigh. His touch sent shivers again through her spine and only made the heat within her worse. He grabbed her thigh, put one hand around the back of her neck gently, and grabbed her cheek with the other. One of his fingers probed her mouth now.

"You really took that thing all the way, made me cum like that on you."

"Yeah, and in me too huh?"

If any cameras were in the room, or any people were watching through, it would've looked like any insane sight. An alien man, sitting on the perch of a bed, using his hands and arms to probe the young coed covered in alien guck.

He turned her head and lifted her chin, eager to see the cum still covering her tongue and roof of her mouth.

"Surprising that it's white, I would've figured it would be red, or green, or grey would make the most sense I guess." Said Sarah. "And I guess you can come a fuck ton of it too. And keep going from the looks of it."

Sarah pushed him back and rose from her position on the bed. The string of spit and cum followed her for a moment and then broke after she was a foot away from the head of his dick. She played her hair to both sides. "You fucking covered me bro. This shit is in my hair, it's on my fucking top too, ugggh."

Even now Mark was amazed that she could care anything about her clothes.

"Can't put in the fucking bin now huh? Not sure how I can do laundry without everyone smelling the cum throughout the house."

She had a point, Mark was going to half to do something about the mess. Not all the cum was captured on her body, nearly a fifth had found its way onto the bed, and the floor. Mark hadn't cum like this ever in his life.

"I can help with the shit on the bed and the floor if you want?" She offered. "I think I should probably try to clean myself off first though." She turned around to lead out the door and looked back at Mark over her shoulder. "Would you... like to help?"

"How long do you think we have until anyone comes home?"

"Well, mom has a happy hour after work today with her office, so I don't think she'll be home until after 7. That leaves us..." she glanced at the computer, used her cum covered hand to do a quick count, "seven hours there. And dad teaches course late tonight. I think he has a lab or something. He's usually not home until what, 8 usually? And I don't see why Danny would come home today anyways, that's probably at least a two hour drive for him. I can check all their locations later, I think we have at least 7 hours then."

"That's plenty of time."

Sarah grabbed one of his hands and led him off the bed.

########## The Shower ##########

She led him out through his door towards the hallway, made a right to go out to the living room.

"Where are we going, shouldn't we go to our bathroom to shower?"

"Hmmm, I wonder why we shouldn't go to our tiny ass little shower? Should we ask the giant 7 foot alien if he might know why that wouldn't work?"

"Oh, I guess you're right."

"Besides just cleaning, I think the shower will give us ample room to, explore."

Mark needed no more motivation. Every moment in this body, with his sister, was like heaven on Earth. He giddily followed her up the stairs and over to their parent's bedroom.

She opened the door and continued to glide towards the master bath. She turned and playfully added "they even have a larger bed" she turned her head mockingly, "I wonder if that would come in handy for a slutty girl and her seven-foot alien plaything?"

When they arrived at the door of the shower Sarah unceremoniously let go of his hand, took her top off, and dropped her panties to the floor. She was acting at completely ignoring her brother, started the shower, and hopped on in.

Mark watched as she turned on the large walk-in showers nozzles until the shower head from the wall began to spray. She adjusted the controls until it started to steam, then got herself into the water. Once in, she found the control for the overhead unit, and had it begin to spray as well.

Mark realized he had probably checked his sister out before, but now she was on full-naked display in front of him behind the glass doors of the shower. Her hair was thick and dirty blonde, her legs and back were toned and wonderful. He had seen the pictures she had posted from festivals, in dresses at formal events, but now he saw the body she was careful to craft and perfect for the world to see.

Sarah worked to wash the cum from her hair and her face once in the shower. Hot water rushed at her and soap fell generously from her hair and her face. When she finally got enough out of her hands and her face to not feel sticky, she looked out from the glass and saw her brother with a slack-jaw look ogling her from the other side of the bathroom. "You wanna come in? I could probably do better with a few extra hands to help wash up."

Mark walked wordlessly to the door of the shower. He used his arms to take his own top off and stepped inside the shower. The water must've been searing, there was massive amounts of steam in the shower now, but it didn't seem to affect Marks new body much. He felt warmth, and approached his sister in the center.

She was facing away from the door when he came in, washing her chest and shoulders. She could feel him approach her, felt the touch of one, then two hands on her waist. He took a knee behind her and then placed a third hand on her right thigh. The fourth and final hand went to her left thigh.

Still cleaning her hair, she urged him on. "You can feel around more, if you want."

Mark moved his upper hands down to her hips, one of his upper hands up to her ass cheek.

He had seen it, even before when he had used the measuring tape, but now that it was up in front of him he couldn't believe that he was lucky enough to be able to grab and squeeze to his desire. He used his hand to grab it from the bottom where the cheek met her leg, then ran his thumb over the top to meet the rest of his hand. His thumb found its way back to the other side of her cheek and he ran the meaty paw up until her ass until he found her lower back, tracing the space between both cheeks carefully.

Even with such large hands, he felt the cellulite (not that she had much in her shape) and dimples perfectly. He took the hand and grabbed a large bite out of her cheek. The shape of her ass and the size of his hands made it incredibly easy, her hips and ass met at an angle and formed a slope to the thickest part of her butt, a way that made it easy to pinch the side with your hands.

"Would you not mind soaping me up alien boy?"

Mark used a spare hand and grabbed a bottle of soap from the she of the tub, held out another hand and poured the soap over his gray palms. He began to lather this sister up, using all four hands to his advantage as his upper arms applied soap liberally to her back, another set to her ass and upper thighs.

Sarah could tell Mark was entranced. She had always considered herself attractive, but the taboo nature of the situation must've captured him.

Mark caught Sarah by surprise when he pressed himself up to her back, arms repositioning themselves to begin soaping her frontside. She could feel his alien breath on her neck now, he must've been fully standing. Both dicks pressed fully into her back, he worked his body so they wouldn't better fall between both left and right cheeks. She moved to steady herself to the wall, grabbing his head with her free hand.

He began moving both hands on her breasts first. Slowly working his way over, to the underside, playing with both her nipples. His hands were large enough that he could cover both breasts efficiently.

His other hands worked their way lower, starting with her waist, then her stomach. He inched his hands down to her stomach, creeping them further down to her pelvis. He landed a large alien kiss below her ear to distract her and took one alien finger to the middle of her pubic hair, then dragged it down to feel her wetness on the lips of her pussy.

"Mhmmm" was all Mark could make out from his sister facing the wall of the shower.

His new digits were grey and long. They looked like they belonged to a basketball player, with large knuckles on his hands and fingers that were thicker than the fingers they belonged to. Twenty of said digits were exploring Sarah's body. Mark used two each from two hands to pinch and squeeze his sisters soapy nipples, all on one hand to hold her wait and keep her steady, and two more to patrol the lips and folding surfaces of his sisters slippery cunt.

He moves those fingers back and forth, using them to tease and probe further without giving too much of the game away.

Mark turned Sarah around to face him. She was as obsessed with his new body as he was with hers. His chest was pronounced, both sets of arms were to die for, his abs chiseled from stone. She put a hand out to feel both his chest and abs. He pulled her close until they were touching, then planted his lips on hers. For a moment they stayed there, lips locked, he pressed himself closer to her, bringing two arms to rest on the all behind her, two others grabbed her ass from behind and brought their stomachs and waists together.

He must've grown since she took him inside her mouth. Both penises rested on her stomach and prevented them from coming closer together. The first moved way when she pressed in further, allowing the second to come in closer and squish the head against her upper thighs. She could feel the bumps making indentations against her wet skin.

Mark's hands worked behind her as they kissed, pulling and playing at the meat and muscle of her ass, teasing at her asshole every third or fourth grab. They played a little tonsil hockey at first while Mark was halfway distracted still with her backside.

When Mark decided he had enough, he probed deeper with his tongue. It was larger than it had any right to be. Sarah guessed that he could probably make her happy woman with that one thing alone. He traced her teeth, the roof of her mouth. Finally he pressed on, pushing her tongue to the side and forcing his way down to her throat.

With a final push of the tongue, Mark slipped one meaty, soapy, large alien middle finger past both knuckles into Sarah's ass. She let out a gasp on his tongue, eyes opened to meet his.

She used both hands to push him off, leaving her back to the wall. "Fuck foreplay." She dropped to her knees in front of him, hitting her chin on both dicks ok the way down. She sat there, dicks resting on both cheeks, cracked the cutest smile, and asked him: "Do you think you're ready to fuck me with these things or what?"

It was all the motivation Mark needed. He grabbing her arms and lifted her up to her feet. Her turned her around again.

"Bend over and put your hands on the wall."

She complied.

Sarah bent over on the far end of the shower wall, away from Mark, and turned her shoulder to see him. She put her hands on the wall and worked her way further and further down. She continued until she had them completely on the floor. "Is that ok daddy? Can I have them on the floor instead?"

Mark didn't need to say yes. He moved his way towards her, his dicks standing at full attention. Sarah had the back of her thighs and her ass on full display to him.

He came to her and grabbed a ledge near them that held soaps and lotions. Another hand went to wall, his lower hands held her waist in place. He rested both on the top of her back and brought his hips forward until their legs met. His balls under him smacked into Sarah and she jumped. Mark took a hand and guided himself against her. He brought the head of the lower cock onto the lips of her pussy and began to stroke it against her labia.

"Mmmmmmphfuck." She growled to the tile floor. Her legs were shaking now that they were getting closer and closer to fulfilling her vision.

Mark pushed the head in and felt the tip slip easily in. He rested it there where the ridge of the head ended and the ridges of his shaft started. "We're not waiting to go all the way Sarah." He brought his second head, the upper, and longer penis, to the edge of her asshole. It was pretty and tight. Mark hadn't tried to slip a finger in that yet, but he figured it would be as willing as her mouth and pussy had been. Something about this body was bringing out a different form of his sister. Something less physical, but different nonetheless.

In a voice almost a whisper Sarah begged Mark. "Please fuck me."

He felt the resistance of her ass squeeze the tip of his upper cock. It felt amazing. He worked his way in, the tip disappearing when the muscles of her asshole brought it in. He was amazed they wouldn't need lube. He had only had anal with one girl before, and she had complained most of the way.

He squeezed in further with both cocks. He could feel each ridge as it passed in, each bump felt like it had a completely different sensation that he could feel in this incredible tightness. His twin dicks felt like they were growing in size inside her, and he felt the movement of each inside her as he began a slow stroke in. He stopped halfway - pulled his manhood out enough to see both holes grip his ridges as he did so - and gave a forceful push in with both cocks. He felt Sarah take him all the way in with her pussy, but his dick made a bend about two-thirds of the way where her ass stopped taking him.

"ooooooohfuck." Sarah grimaced and her left leg started to twitch.

"You're going to have to bear down a little harder if you're going to take it all the way." Mark told her, more as a matter of fact than as a taunt. He brought one hand to a slap on her ass. "Are you going to be a good girl and take me all the way?"

"Yes I'll, fuck... yes I'll be a good girl." Her leg continued to twitch.

Mark used the moment to send a strong twitch of his own through both cocks. He could feel her leg shake in response, as if he sent a signal straight to her brain. "Ask your brother nicely if you want it to go deeper Sarah."

"Please.. fuck umm.. please go deeper Mark I can..." Sarah let out a low groan. "fuck me please, I can take it baby."

Mark worked both dicks out and in now, keeping both two-thirds of the way. Ridges ran up against the edges of both her holes now as he started to hit a comfortable pace. He figured if he had any change of getting all him in, it would require a little bit of rhythm and finesse. Sarah was silent now aside from the occasional grunt. He could feel her getting wetter and wetter with every push, her feet raised so that she was standing on her toes. His dicks began to slide with ease with each thrust he gave her, both dicks finding their way deeper and deeper, her ass taking him in now nearly to the hilt of the upper penis.

With all the teasing she had given him in his bedroom, he figured some teasing of his own might help send her to the edge.

"You.. haven't.. got.. dick... like, this... before... have you?" He lost his voice a little between each thrust.

"I haven't, FUCK. Got. Dick. Like. This. Before." She enunciated back to him.

"What's the biggest, dick... you've, got?"

"Fuck.. oh fuck.. not anything this big Mark." Her eyes were closed now, both legs shaking from the effort.

Mark figured he was due for one final effort. He could feel his own orgasm closing in.

He grabbed her hair and lifted her head from near the ground. She brought her arms up and continued to brace on the wall. He was hitting each stroke into her perfectly, staying a little out of her each time so he could orgasm on the finale.

He had a controlling hand with a solid grip on the base of her dirty brown locks. One still gripped her waist tight, thumbs and fingers nearly wrapping themselves all the way around her waist. His other hand held the wall, and his final hand had a grip that would leave a mark on her ass when he let it go. He was pushed in almost all the way to her now, balls slapping her stomach when his rhythm brought them far up enough. He braced himself for the final push.

Sarah's legs still shaking, her teeth gritted tight, Mark made a series of final pushes with his hips. His pelvis met her ass and sent ripples through both cheeks, nearly pushing her head fully into the wall. With each motion Sarah's legs grew tighter and tighter, nearly rigid, and she pushed herself towards the ceiling with her toes.

"I'm gonna finish inside you, you're gonna have to shower all over again. Fuck, fuck, fuuuuuck."

With a final push, Mark pulled Sarah's head back all the way with his hand, his pelvis on her ass fully. He felt both dicks twitch violently when they erupted, sending his alien cum deep inside both her holes.

Sarah, on the other hand, felt heat and electricity erupt through her in what was unarguably the deepest and most intense orgasm she had ever had in her life. For a moment she lost all track of time and space and fell into a small black hole of pleasure. If she had any feeling left of the real world, she would have felt cum oozing in and out of her, bubbling between her own skin and that of Mark's cocks.

Mark took his time easing out of her body. He grabbed her arms with his and held her waist in place. She was clearly in another world now, but he had to keep her upright so he could enjoy more of the show. Still somewhat erect, he pulled both dicks out of her slowly, savoring the view of the glazed dicks sliding and pulling the skin of her ass and the lips of her pussy. They both came out of her holes and limped back down to his legs. He was certain that his dicks could go at least a few more rounds, but Sarah would be down for the night.

Mark let Sarah down onto the tile, laying her gently. She wasn't outright passed completely out, but she was somewhere in between consciousness and sleep.

As Sarah came to, Mark was washing his alien body off in the shower. Muscles wet and soapy, he was using all sets of arms to clean himself off. His shoulders worked and flexed as he cleaned himself, paying special attention to two slimy and spent members. She wordlessly got up and began to clean herself as well. She could feel his alien seed still oozing out of her in drips as she cleaned up next to her brother. Still, she just had the most satisfying sex of her life in her parents shower, and there was plenty of cleanup still to do around the house, she could worry about alien impregnation tomorrow.

########## Interlude ##########

"Clean sheets, clean floor. You made sure you cleaned mom and dad's shower thoroughly?"

"It's not the first time I've cleaned a shower Sarah. I even used two-dicks to do the cleaning."

"Is that what we're calling it, two-dicks? Seems a little too on the nose. And did you use two dicks, or your arms?"

"Ha ha ha. Very funny. Whatever we want to call it, we should be in the clear. Do you think anyone will find it odd that we used the carpet cleaner in my room?"

"No probably not. I mean, you're a young man living with his parents. You probably spill soda and shit in here all the time. If anything they'll just be happy that you cleaned it up."

It had been hours after their tryst in the shower, and still hours before Sarah or Mark's parents would be home. Mark had used his watch to swap back into human form quickly after cleaning his parent's shower. Sarah had since cleaned herself, both inside and out. She had decided it would be prudent to put on a pair of pajama shorts now, plus a shirt of Mark's. Better to clean alien cum out of one of his old gym shirts than one of her best tops again.

"Hopefully no one comes in here trying to smell anything. You can practically still smell the cum. Speaking of cum, mind if I put my stuff in your hamper? I feel like it's been a while since mom has bothered to touch your laundry."

"Not a problem at all." Mark replied from the bed. He examined his watch, flipped his wrist around examining his new prized-possession.

Sarah took a last look at her top before throwing it in his closet. She grimaced and held it up with one hand. "You really blew a load on this one dude. You better make sure you use extra detergent when you throw this one in." He didn't spare a look, she discarded the top.

"Yeah yeah yeah. You know you really only have yourself to blame for that."

Sarah walked over to the bed and casually threw herself next to Mark. They were both laying, him staring at the watch her staring at the ceiling. She pivoted her hips so that she would be closer to him, landed a foot next to his leg.

"Has anyone ever told you that you look like that blond girl from Euphoria? The one that hooks up with her brother's best friend?"

"Sydney Sweeney? Get the fuck out of here that is so ridiculous."

"I mean it! You really do. I looked up her measurements and you are both practically the same. I don't know what your bust size is though. I don't think we got to that measurement."

Sarah propped herself on her elbow and looked at him, still admiring his watch. "You know, flattery won't get you anywhere. You've already violated me with a four-armed, two-cocked alien body. There's really no advantage here to lying."

"I promise I'm not being dumb. I'm not fucking with you, it's true."

"Oh and acting like you don't know her name by heart? Come on."

Mark rolled his eyes. Of course he knew Sydney Sweeney's name by heart.

That night, while Mark and Sarah slept in their respective rooms, while his mother and father slept peacefully and unaware of the days events, Mark's wrist lit up. An inlet of his alien watch grew a new spark of electricity.