System-Y

Content Warning: muscle expansion/growth, excessive masturbation, giant dick and balls, breeding kink, oviposition, egg laying via dick, sounding, alien parasite, sex obsessed, voyeurism, mpreg

"Dax! There you are, dude, finally!"

Fresh off his security detail, Dax turned when his friend Fletch called out to him in the locker room. "Hey, man, long time no--" he began as he turned to look at the other man and stopped short, jaw all but dropping at the sight that met his eyes.

He and Fletch had been born and raised in the same colony on Mars so while they hadn't actually known each other as kids, their shared hometown had given them something to bond over when they'd both wound up assigned to the same platoon two years ago. They'd become fast friends since though hadn't seen each other in over a week since being assigned to opposite shifts after arriving on Watch Station-416. After months on the front lines of what the feeds had started calling 'the galactic civil war' the news they were being rotated to a low-risk region well within Alliance borders had been welcome.

Everyone in their platoon was more than ready for a little boredom.

Everyone except Fletch, apparently-- he looked like he'd somehow managed to squeeze six months of heavy lifting at the gym into a single week.

"Holy fuck, Fletch, the hell you been doing? Did you move into the gym full time or something?" Dax demanded incredulously and grabbed his friend's bicep. It was rock hard when he flexed it and way bigger than it'd been the last time they'd seen each other in the mess hall.

The other marine laughed as he opened his locker and stripped off his shirt to get dressed for his shift. Dax couldn't help but stare-- his friend was absolutely shredded. They had both been plenty muscular the week before-- the peak of health and fitness per standard marine regulations, but this was a whole other level of bulk. So much so he couldn't help but think the other man even looked taller, though he wrote that off as just his imagination.

"Not exactly," Fletch replied evasively. When Dax kept staring at him expectantly, though, he relented and waved his friend in closer to speak in a voice just above a whisper so the rest of the marines in the locker room wouldn't overhear. "I found this new bit of hardware at a shop down on deck thirteen-- been using it all week and its done wonders."

Dax let his eyes rove over Fletch's rippling pecs, thick forearms, and narrow waist. "No shit. What shop? I have got to get me some of that," Dax pleaded. Deck thirteen housed the docks for civilian merchant ships so a lot of shops had cropped up there to avoid the additional taxes that came from selling on the upper decks where they did actual quality control and import inspections. He hadn't been himself yet, but he'd heard you could find all sorts of fascinating, questionably legal stuff there if you knew where to look and who to ask.

Leave it to Fletch to figure that out within a few days of arriving on station.

For a moment Fletch hesitated, almost seemed like he wasn't going to answer Dax, then seemed to change his mind. "Little shop way back in the north-west corner of deck thirteen; wedged between an after-market wetware clinic and a junk shop-- you'll know it when you see it. Just ask for a 'System-X'." He straightened then, and in a normal voice, said, "Its your turn to take leave for the next week, right? Have fun!"

~~~

The shop, unlabeled like most of the places in this section of deck thirteen, was tucked away in a particularly quiet corner where no one made eye contact or pretended to notice anyone else they happened to pass in the narrow alley. Determined not to stand out Dax did the same and entered the cramped, tiny shop to address the nondescript woman stationed behind the counter.

"Hey, I'm looking for, uh... for a System-X?" Dax asked, voice low as he leaned against the counter.

"Oh," the woman said, plainly surprised, even perturbed by the request. She glanced up at what Dax realized was a security camera in one corner and said, "I wasn't told we were giv-- selling anymore of those. Where did you--"

Just as Dax was beginning to suspect Fletch had walked him into a heap of trouble the woman paused, head cocked slightly to one side as if listening to something he couldn't hear-- entirely possible considering how discreet earphones were these days.

"Actually," she said and smiled, "we're out of the System-X but we do have a System-Y available!" Seeing the doubt on his face, she pressed, "Oh don't worry, it's the same thing, just a newer model! If you don't like it, bring it back within seventy-two hours for a full refund-- no questions asked!"

That should have been the moment he knew the offer was too good to be true, but blinded by the low price she quoted him and the memory of Fletch's impossibly bulked out physique Dax caved and immediately bought it.

"So, how do I use it," he asked when she passed him an unlabeled box across the counter.

"Oh, directions are inside! Feel free to come back by if you have any questions, though," she said with a wink then proceeded to shoo him out of her shop and close up after him.

A little nonplussed by the whole affair, Dax went back to his quarters (the backwater space station was spacious enough that even rank-and-file like him got their own room for a change) and locked the door behind him before he tore into the box, eager to finally discover what all the fuss was about.

Inside was a canister about sixteen inches long, about the size of his forearm, and he didn't have to look at the instruction card in the box to figure out that 'System-Y' was a flesh-light.

"Fletch, you asshole," Dax complained aloud with a groan of frustration. If his friend hadn't wanted to share the secret to his sudden gains he could have just said so instead of sending him on a wild goose chase for a goddamn pocket pussy of all things.

Annoyed and already plotting revenge, Dax tossed the flesh-light onto his bed and went out get himself some dinner. By the time he returned an hour later his ire had faded enough to allow curiosity to take over so he took up the thing and inspected it. The design was exceedingly simple-- a basic cylinder with some grooves to make grasping it easier as well as a screw on cap to cover its mouth when not in use. Unlike standard offerings of the same type of device, this one had no labels on it at all-- not even a brand name.

More curious than ever at this strange state of affairs, Dax unscrewed the cap and watched as the material within expanded outward by several inches to simulate a particularly plush set of labia, though only the large outer lips-- beyond those was a wet, fleshy hole. Dax pushed two fingers inside and was shocked to find it didn't just feel slick and warm (standard offerings for such a device these days)-- it felt alive.

Startled by the thought, the marine dragged his fingers back out again and immediately picked up the instruction card that had come in the box. Said 'instructions' were simple enough and boiled down to 'insert dick, fuck to completion', as one would expect, though on the back of the card he did find more information about the materials involved.

"Syn-flesh," he murmured aloud as he read. He'd heard of it before-- mostly you saw it used in medical procedures where you needed to regrow a lot of muscle or other tissues after a traumatic injury. More than a few people in his unit had skin or muscle that had been custom printed for them in a med-lab to replace what had been lost.

Dax wasn't entirely sure how he felt about using living tissue as a fuck toy-- even if it wasn't attached to a larger organism or capable of feeling pain, but there was no denying that the toy itself felt amazing...

"Fuck it, why not?" Dax mused after a moment's consideration and dropped onto his bed. His new purchase wasn't about to get him as jacked as Fletch but having a new toy to jack off with over his week of leave wasn't bad either.

It was, in fact, amazing.

Dax barely managed to last more than a minute after pulling his dick out of his pants and slipping it into the mouth of the flesh-light before he was pumping a load into the thing.

"Ooooh fuuUUUuuck," he groaned loudly, hips jerking unsteadily as he stroked himself with his new favorite toy. He'd never felt anything quite like it-- it was more than just a pussy, it was pleasure incarnate wrapped flush around his cock, spasming and flexing along his length in a perfect counter-tempo to the speed of his thrusts.

It was the perfect temperature too, and slick enough that he could continue to thrust into it even when it had him gripped like a vice.

"The fuck is this thing?!" Dax moaned as he caught his breath and pulled it free of his cock with an audible slurp. He looked at the card again but the only thing he learned was that if the outer plastic casing broke the sleeve itself could still be used so long as you kept it in water between uses.

Eager for more and already hard with anticipation, Dax stripped out of his clothes and settled in for another go, determined to last longer now that he knew what to expect. The marine tried to keep a slow pace at first but it wasn't long before he was jerking himself off with the thing just as fast as his arm could pump, hyper-focused on the sweet, hypnotic slide of the synthetic pussy up and down the length of his cock.

"Yes! Oh god, yes," he whimpered, body coated in a fine sheen of sweat. "Gonna fuck you so good," he panted, mouth hanging open, tongue lolling as he lost himself to pleasure. This time, though, just as he reached the brink of orgasm, something inside the sleeve pressed into his urethra and slid down into his shaft, making his eyes fly wide open as he gasped and twitched his way through an orgasm even stronger than the last. Whatever it was inside of him was strong enough to forge a path halfway down the length of his dick, but supple enough that it bent with him to prevent injury. "Fuck! FUCK!" he screamed as the hole he was fucking fucked his hole in turn and siphoned off his seed while his body attempted to ejaculate.

The person in the next room over banged on the wall but Dax didn't pay it any mind as he lay on his bed covered in sweat, trembling, head spinning in the wake of his orgasm.

After laying there on his back with his dick still trapped in the flesh-light Dax pulled it free again, moaning pathetically at the twin sensation of pulling out while it pulled out of him.

"Seriously, what the fuck," he panted incredulously and took a closer look at the strange flesh-light. He stuck a finger inside again and jerked it back out again when he felt something coil around the digit. A thin, fleshy tendril of some sort came with it, prodding blindly at the tip of his finger as if in search of something, and Dax realized this was what had been sounding him. "What, you want more already?" he asked absently, squeezing it gently between his fingertips when it began to retract back inside the sleeve.

Pleased to find the toy came with a self-cleaning function Dax cleaned himself up and went to bed after that, resolving to wake up at a reasonable hour the next morning to get a few errands done.

The marine dozed for awhile, but tossed and turned well past midnight when he woke fully to stare at the ceiling for awhile until he broke down and reached for the flesh-light.

"One more won't hurt," he mumbled, cock already stirring in anticipation. He'd sleep better if he got off again-- he always did.

Wanting to save his arms, Dax bundled up his pillows and wedged the flesh-light into them so he could effectively fuck it doggy style with the pillows serving as leverage.

"Hnnngh, yeah," he moaned as he slid inside, eyes fluttering shut as a gentle, mind-numbing bliss settled over him like a weighted blanket when the sleeve enveloped him in a welcome embrace. "That's it..."

He set a slow pace at first, pulling his hips back until the tip of his cock just kissed the sleeve's plush, slippery outer lips, before pushing gradually back inside. He relished every inch, the way the syn-flesh molded itself perfectly to him every time so it was a tight fit without being too tight-- like a wet, cock-starved virgin lay splay-legged and desperate beneath him just begging for it.

The tentacle penetrated him again, drawing a low bestial groan from the marine and driving him to thrust faster in an attempt to force it deeper inside of him. It probed and writhed along the inside of his shaft with a mind of its own until Dax was panting and humping his pile of pillows like a dog-- all thoughts of getting off quickly so he could go to sleep forgotten.

It reached the base of his shaft and kept going-- the feeling one he couldn't quite put words to. The sensation of something penetrating all the way down into his balls was simply indescribable.

"Fuck-fuck-fuck-fuck-FUCK," he panted into the velvet dark of his quarters in time to his thrusts, bed rocking roughly under the force of his enthusiasm. He'd never had sex with a partner feel as good as what he was getting from the System-Y and when it sucked his cock and pushed deeper into his balls at the same time as he came a moment later he knew he'd probably never be able to go back.

His balls seized when the marine came and the sensation of them going taut around the tentacle that had forced its way into them to feast on his seed at the source made his orgasm feel like it lasted a lifetime. The grunts and groans of a desperate animal were all the noise he could make through it all until, finally, he flopped bonelessly sideways onto his bed, trembling from the exertion and the pleasure.

The tentacle pulled free after a minute and the sensation of it being dragged out of him made the marine swear and shake and nearly come again. When it finished, he pulled the sleeve away and rolled onto his back to examine himself after clicking on the bedside lamp. His cock was swollen and red, like he'd been using a pump, and while it was difficult to look at them, his balls felt... swollen-- as if they'd been filled with something rather than been emptied.

They felt good-- hot and heavy in his hand. So did his cock, which was still semi-hard and getting harder by the moment.

"One more won't hurt," he repeated himself groggily without even realizing it.

~~~

Sleep didn't claim for an hour or more after that and if he was being honest he didn't actually remember making the active decision to go to sleep. When he woke, he was sprawled naked on his bed, flesh-light on the side-table, and he grabbed it without a second thought the moment his bleary eyes landed on it. The insistent, pleasurable ache of severe morning wood was immediately soothed by the sleeve's warm, supple embrace and Dax was jerking himself off before he'd even woken up enough to register the time.

He came quick and hard with a low, shuddering groan, bare body threatening to break out in a fresh sweat as the System-Y drank deep of his seed. It didn't even have time to penetrate him in turn he finished so quickly.

The sleeve was blessedly self cleaning, but the same couldn't be said for Dax so the man rolled out of bed and went to take a shower, bringing his new toy along without even thinking about it. The heady rush of the hot water over his body while he fucked the flesh-light was a new kind of ecstasy that lead to him linger under it's spray unleashing load after load as his cries of pleasure echoed in the tiled room, filling his ears with a cacophony of his own gratification until the water ran cold.

Only then did he register just how hungry he was -- chill water granting him enough clarity of mind to feel a modicum of shame at how much time he'd wasted masturbating like the galaxy's horniest teenager.

Dax dried off and put the System-Y aside then turned his attention to his pressing hunger. The quarters he'd been granted were made up of a mid-sized room with a bed, small sofa, kitchenette, and on suite bathroom-- an extravagant luxury after months on the front-line sleeping in a bunkhouse. Happy to cook after so long on rations, Dax threw a few things together he'd bought the day before in preparation for his leave, then sat down to eat on the sofa while he watched some TV.

The programming didn't do much to hold his attention, though, and soon the marine found himself idly playing with the flesh-light in one hand while he ate with the other. Then, caving into his most hedonistic impulse yet, he dragged down his sweatpants and slid the sleeve home onto his still-restless cock-- just to keep it warm while he finished eating.

Once it was on, though, the sleeve's fleshy interior began to stroke him off of its own accord, as if just as impatient as he was. Dax moaned around a mouthful of food and swallowed hurriedly.

"Fuck, oh fuck," he muttered and forced himself to quickly demolish the rest of his meal before he rolled over, pushed the flesh-light down between the cushions of the couch back, and proceeded to fuck it with wild abandon. Anyone who had walked in unannounced then would have been treated to a view of the marine gripping tight at the couch's frame as he fucked the pillows like a dog, mouth hanging open and tongue lolling to complete the picture.

Completely eaten up by lust, Dax couldn't even hear the TV anymore as he panted and fucked the System-Y, let alone remember the plan's he'd made to leave his quarters to run errands. He found his way back out of his clothes and soon all the work of his shower was undone as the marine soon became soaked in sweat once more as he pounded the sofa, its cheap metal frame beginning to rattle and groan under the onslaught.

"Take it," Dax grunted, every muscle tensed and working as he chased his release. "Take it-- take my cock!"

He came again with a shout and inside it's hard plastic case, the System-Y squirmed and milked him for every ounce of semen it could wring from his increasingly swollen balls.

~~~

Dax lost all sense of time after that, as well as the number of times he'd orgasmed, but on day three he came back to himself enough to register his own reflection in the mirror when he passed it on the way to masturbate in the shower again. Ironically he'd been showering a lot more than usual, once every few hours, but not because he took any notice of how sweaty he'd gotten-- it just felt that good.

The man that caught his eye in the mirror made even Dax's lust addled mind pause and delay its next round of sexual gratification long enough to take a good look at himself.

He looked like Fletch.

Not literally, of course, but his body had gone through the same extreme changes. Dax was more muscular than he'd ever been in his life and he was pretty sure he was at least a couple of inches taller. His dick, too, he realized as he ran his hands down his chiseled abdomen to its base, was significantly bigger in both length and girth. He'd been pretty big in that department to start with but now he looked like one of those holo-porn star studs with augmented dicks that pushed the limits of what a standard human hole could reasonably take.

"Holy fuck," he groaned, half-hard cock swelling further, stiffening to stand straight out before him with a vigor and strength you could have hung a weight from.

Fletch, it seemed, hadn't been yanking his chain after all.

Dax grabbed his massive pecs and squeezed, marveling at their size and the heightened sensitivity of his big, pert nipples. Those had grown significantly in size from how they'd been a few days before-- more than his pecs or even his dick. The dark areolas were puffy and the tips thick and stiff; just begging to be sucked.

His balls had swollen visibly too and now hung like two ripe plums between his heavily muscled thighs looking for all the world like they'd never been emptied despite all the semen the marine had been pumping into his new favorite toy for the last few days.

Remembering the System-Y where it still rested in his right hand, Dax looked at the thing and marveled at it-- way too far gone now to be anything but thrilled by his unnatural metamorphosis.

"More," he mumbled to himself and slid the sleeve onto his cock once more. Rather than get into the shower this time, Dax jerked himself off in front of the mirror, hypnotized by the ripple and flex of his muscles and the heavy sway of his balls. The flesh-light was becoming a tight fit on his expanding cock as it strained against the confines of its case to accommodate him. Dax barely noticed, though, he was too busy staring at his reflection and playing with his nipples to register the cause of the increasing tightness.

The case finally gave way a few hours later, cracking with the sharp snap of brittle plastic pushed past its limits and all Dax could do for a moment was stare stupidly down at the thing where it was still wrapped around his dick. He was in the shower, warm water cascading down his powerful body and when his brain finally caught up, the marine pulled away the pieces of broken plastic and cast them aside. Fortunately the thing had broken clean along the seam that ran down it lengthwise so there wasn't any shrapnel left behind-- just a pinkish mass of flesh that throbbed subtly in his hand in time to his own heartbeat.

A quick look was all it took to know it wasn't just the rough and relentless use Dax had been putting the sex toy through that broke it. The flesh within had... grown. Its mass combined with his dick was simply too much for the frame, leaving the marine with a warm, pink, pulsing sleeve wrapped around his cock.

"No, no no no," Dax whimpered, disturbed by the thought the flesh-light might be beyond saving. He needed it! Needed more, it-- it slipped its tentacle down the well traveled and much expanded path of the man's urethra and a soft moan of relief that escalated quickly into rapture rose up from within him. It tightened around Dax's cock like one massive muscle, squeezing him, gentle but firm-- as if trying to reassure him.

Or like it was asking him to continue.

Dax took himself in hand again, gripping his cock through the soft, muscular sleeve, sliding it up and down along his length to ride that unending wave of pleasure it granted him once more.

~~~

Five days later, the same day Dax was supposed to report back for duty, the man stood in the shower, hands pressed to the wall, breathing hard and feeling strange.

The fact he was late to work didn't even cross the marine's rut-fogged mind-- he was too focused on the strange, uncomfortable swell of a bloated belly he'd woken up with after finally fucking himself into exhaustion in the wee hours of the morning. His balls felt swollen and taught as a pair of beach balls too, though he couldn't even begin to try getting a look at them over his stomach.

He looked like he was two trimesters into a pregnancy that couldn't possibly be real. The surface of his stomach was stretched taut as a drum with no give at all when he ran one hand over it and for some reason the sensation aroused him. Then again, everything aroused him these days and and his gargantuan cock stirred sluggishly in response.

Dax hadn't removed the fleshy sleeve in... days? Had it been days? He couldn't remember and he didn't particularly feel a need to so the marine let the question drift away into the ether where most of his increasingly infrequent non-sexual thoughts went these days. Regardless, it was hard to tell where syn-flesh ended and his own began as it hadn't just changed colors to match his skin-tone, but mimicked the shape of his actual cock blown up to a monstrous scale. If not for its human shape one might have thought the thing had been grafted onto Dax from a particularly well hung horse.

His stomach gave a twinge and reflexively the man dropped into a squat-- at first just to keep from falling over and then to follow some instinct he'd never had before. His engorged, melon sized balls rested on the floor beneath him as the man leaned forward so he was squatting on all fours like a gorilla, grunting and panting like one as something shifted deep within him.

He felt on the verge of orgasm again despite not having even touched himself and, chasing the feeling, Dax thrust his hips like he was fucking some unseen hole, the motion making his massive dick bob and sway until he got the rhythm right so it slapped meatily against the wet floor, further stimulating him.

"Fuck," he moaned, eyes rolling back in his head as he rutted uselessly at the air, dick slapping the ground like a pathetic, mindless breeder in pursuit of any stimulation at all. "Gotta fuck, gotta-- "

He came, then, and his moan escalated into a bestial roar of effort as something new happened. Rather than another load of thick, hot seed erupting from his gaping urethra, there was a delay as something much larger was gradually forced along the full length of his cock from deep in his body before springing free.

Eggs, he realized after a dazed and confused moment of staring at the first of them when they dropped from the head of his cock. Eggs the size of marbles were being jettisoned from his packed bladder and balls a dozen at a time as he howled himself through an orgasm that lasted for ten minutes straight, driving him delirious with the nerve-rending pleasure of it all.

Overwrought by the experience, Dax blacked out in the bottom of his shower surrounded by the strange eggs he'd birthed.

~~~

Agent Alpha stared down at the recipient of the new System-Y they'd developed where he'd blacked out in the shower and wondered what the higher ups had been thinking unleashing it so soon. Not only had the thing fused with its new host but it'd already replicated itself-- though whether the eggs were viable was a question for the boys back at the lab to figure out later once he'd collected their new specimen.

"Fucking Christ, look at that monster," Agent Beta said as he entered and joined Alpha in staring down at the marine once known as Dax. "The changes are an order of magnitude-- no, two greater than the System-X" the agent continued, clearly impressed. Clad in the same head-to-toe med-suit Alpha was, Beta nudged Dax's new massive cock with the toe of his boot with a soft whistle. "Full fusion. We were hoping that'd be the case, but damn."

"Another thing seeing it in person, huh?" Alpha mused and Beta nodded. "Well, we'd better--" Alpha began, then stopped when Dax moved unexpectedly, lunging to his feet in a blur of motion and catching Beta by the neck before either of them realized what was happening. "Fuck!" he yelped and jumped away as the former marine loomed over them both. He grabbed the tranq pistol from his belt and shot the goliath with it but the dart didn't seem to do anything at all as Dax dragged Beta in closer, monstrous, parasitical cock beginning to twitch and swell.

"What is-- oh fuck," Agent Gamma exclaimed as he entered from the main room where he'd been examining the test subject's living quarters.

He went to pull his tranq pistol as well but Alpha waved at him to stop. "Don't bother, he'd metabolize it way too fast!"

"Then what do we do?!" Gamma demanded, panic entering his voice behind his mask.

Thinking fast, Alpha said, "Bring in that other new subject we collected on our way over! We'll use him as a distraction!"

"What? Are you sure?"

"Fuck it, they're both going to be part of the breeding program anyways-- or would you rather him try to start with Beta?"

Gamma looked back at Dax and Beta-- the former marine's cock was fully erect and nearly as long as Beta's torso when he rutted against it, as if testing the waters. He swore again then rushed out of the room.

Fortunately, Gamma returned only moments later leading a second man on a leash. He wasn't so large as Dax but he still dwarfed the agents around him so they'd put him in a blindfold and gag, as well as an arm binder, to keep him well under control. Just as nude as his fellow marine, this man's cock was a tiny stub of what it had once been, but his hole was swollen and twitching, like a pussy begging to be pounded. He was nearly as muscular as Dax but his own metamorphosis had also granted him a snatched waist and wide, child-bearing hips that drew every male eye, no matter what their sexual orientation.

Semen dripped from his permanently gaping hole and Alpha noted that Agent Delta must have been more 'hands on' than he was supposed to while guarding him back in the transport. He made a mental note to chastise him later but for the time being he snatched the subject's leash and dragged him into Dax's line of sight from the bathroom.

"Hey, stud, come get a proper bitch!" he called and slapped the newly arrived breeder on his round ass to get Dax's attention.

~~~

It took a full minute for Dax to recognize Fletch-- his friend had changed nearly as much as he had. Had this been the version of Fletch Dax had seen in the locker room when the man had suggested he invest in a new 'toy' Dax would have been horrified rather than impressed. Now, though? Now he was aroused.

Something about his friend called Dax in a way the squirming, frightened, tiny excuse for a man he'd caught by the neck when he came around didn't. A primitive part of him reawakened by his transformation howled to be sated and Dax succumbed to the call without resistance.

"Mine," he ground out roughly and dropped the stranger without a second thought to advance on Fletch. The man holding his leash released it and sprang out of the way just in time for Dax to bear the other transfigured marine back towards the bed.

Arms still bound, Fletch toppled helplessly backwards onto it and Dax took a moment to stand over and drink in the sight of his beautiful body. A few inches shorter than Dax the other marine was still stacked with heavy, perfectly sculpted muscle but his pecs were heavier, more like breasts that suited his narrower waist and wider hips. His cock, roughly the same size as Dax's own just a week previous, had shrunk to a stub of its former glory and his balls seemed to have withdrawn entirely.

He'd been transformed into the perfect breeding bitch for a man like Dax.

Elated by the realization, Dax moaned a little to himself and ran his hands up Fletch's sculpted abs to grip at his tits and tug roughly at his puffy nipples. The other marine squirmed but couldn't pull away or make a sound thanks to his bindings, a fact that made the stud's fat cock perk up even faster.

"Mine," he said again, low and fervent again as he pressed his nose into Fletch's neck, inhaled deeply then manhandled him over onto his stomach.

With his ass in the air it was easier to get an eye full of his hole-- the once tight ring of muscle swollen and gaping, dripping not just come but some sort of lubricant his body now seemed to produce. Too far gone for foreplay, Dax took his stance behind his friend, grabbed him by the hips and pressed the fat head of his monstrous, uncut cock against his waiting hole.

Fletch squirmed a little when the glans breached but otherwise didn't protest until Dax had put a full foot of cock up his ass. It was widest at that point and stretching even Fletch's incredible hole to its limits as he pushed deeper and deeper into the feverish confines of his powerful body. Soon the other man was screaming into his gag and writhing under the harsh, unrelenting press of Dax's cock but the marine held him forcefully in place, determined to sheath himself fully. He never would have been so rough with a lover in the past but now he was driven by instincts that pre-dated humanity-- instincts that insisted you didn't coax a lover...

You took a mate.

The bitch writhing and moaning beneath Dax was his-- he just didn't realize it yet. The foolish, whimpering creature didn't have any concept of how blessed he was to be taken by a stud like him, nor did he have any idea how many elite, genetically enhanced soldiers he was going to give birth to from this day on.

Technically speaking, neither did Dax-- the man's higher reasoning had checked well out and all he was actually thinking was how desperate he was to fully sheath his cock in Fletch's squirming body.

Gentleness a concept he no longer had any grasp of, Dax leaned over Fletch, braced himself against the mattress, then pushed his hips forward to force one gut-stretching inch of his mutant, syn-flesh cock after another into the other man's ass. Fletch howled into his gag at the abuse but he didn't thrash or otherwise lash out against Dax either, as if his body craved this brutal rape even as his mind defied it... and inevitably broke.

Dax finally sheathed himself to the hilt in his friend and released a low, animal groan of depraved gratification at the tight heat wrapped around his full length at last. It felt good. It felt so fucking good but Dax didn't have the words to express the satisfaction radiating through him at not only being inside of Fletch, but so utterly dominating the other man who now sagged limp and submissive beneath his beastly bulk.

Primitive, bestial instincts amplified by the chemicals flooding into his system from his new mutant cock eroded Dax's higher intelligence a little more with every moment that passed until fucking the bitch under him was the only thing he could think of.

Primed and ready to breed, Dax began to thrust.

~~~

"Fucking Christ, look at him stretch," Beta said, having picked himself up off the floor after being abandoned by Dax and joined the others to observe.

"Shouldn't... shouldn't we stop them?" Gamma suggested sheepishly, eyes jumping from one corner of the room to another under his mask, like he wasn't sure where to look. Always, though, his gaze returned to the rutting meta-humans on the bed a few feet away.

"You wanna try, you go ahead. I'm staying over here," Alpha answered bluntly, his own gaze riveted on the marines. Well, former marines. He wasn't sure what they were now beyond monstrous and horny beyond all reason.

He should have been disgusted watching the violent rape playing out before him-- the one he'd instigated by bringing Fletch in as bait for an unrestrained stud the likes of which their tests had never before produced.

Instead, Alpha couldn't tear his eyes away, marveling at the powerful ripple and flex of Dax's swollen muscles as he fucked down into Fletch's helpless body. Bound and gagged there was no way the smaller man could resist his attacker but the longer they watched the more convinced Alpha was Dax had managed to break in and subdue Fletch to his will the moment he'd forced the man to take his entire cock.

Heart pounding in his chest Agent Alpha felt the blood surging to his own cock as he watched, stirred by this display of fanatical, zealous breeding. A fine sheen of sweat was breaking out across the pair's impossibly sculpted bodies, lending them a glow in the apartment's low lighting.

Thank god his suit camera was recording. It shouldn't be too hard to transfer a copy of what he was witnessing to his personal drive for... later use.

~~~

Rendered blind and mostly mute by the mask his captors had put on him when they'd caught him on a days long masturbation bender with the System-X in his apartment, Fletch had no idea where he was but he did know that the dick being rammed up his ass and into his body had left no room for thoughts in his head, only mind-bending pleasure at being fucked like a living cock-sleeve.

The System-X had been the perfect dildo-- able to move and expand inside of his ass to hit his prostate or whatever other part of Fletch would get him off faster and it hadn't been long before he'd become addicted. The sudden muscle growth had been a great perk but it'd been days since he'd cared about that-- all he wanted after awhile was to be permanently filled with that fat, squirming, and ever-expanding living dildo.

Eventually he'd stopped taking it out at all and, while he didn't realize it now, the thing had fused with his body to form the new thick outer lips of his asshole and the womb within. While he was unaware of his new organ's existence, its hunger for cock had been on the verge of driving him mad until, finally, a cock fat enough to sate it's lust to be filled forced its way inside.

Fletch could hear the heavy, laboring breaths of the beast raping his pussy behind him and knew his own massive form had been dwarfed by his new mate. Still laid out on his belly, the marine arched his back to let that barbarous cock deeper into him, eyes rolling back behind the mask while he panted and drooled into his gag like a dog in heat.

Harder, rape me harder! He wanted to scream but no longer had the wherewithal to string the words together coherently, leaving him to moan and grunt, incoherent with lust instead. Turn my hole inside out with your fat cock-- use my body! Ruin me!

As if sensing his thoughts, Fletch's mate pulled back some, then grabbed him by the binding that held his arms behind his back and hauled the man semi-upright for leverage. He renewed his assault of Fletch's hole then, pounding into him harder than ever so the sound of their skin slapping together filled the room, drowning out all else but their heavy breathing and bestial moans. Fletch couldn't see it, but he could feel the way his abdomen bulged outwards with every thrust of the other man's cock into his body.

He wanted more, though, wanted to be filled with the other man's seed until his belly bloated with it. Until he was filled from end to end so it gushed from every orifice...

~~~

Close... Dax was so fucking close now! He'd well and truly broken his bitch in now, leaving him pliant and obedient to his every wordless demand to submit for his pleasure, his release, and they were ready.

Eager to finish, Dax released Fletch and dropped the smaller man onto the bed and pulled out. The slut protested into his gag at suddenly being left empty, his hole twitching and grasping at empty air until Dax tore off his arm binder and rolled him onto his back again. He pried the mask off too but blind lust left both men unable to recognize the other beyond their new roles as breeding stud and broodmare.

Fletch spread his legs and Dax forced his way inside again, relishing not just the warm, tight embrace of the man's hole around his dick, but the way his belly bulged outward to accommodate him. The stud dropped to pin his bitch to the mattress then leaned in to kiss him as hard and rough as he fucked him. Fletch moaned into his mouth and Dax sucked forcefully on his tongue then pushed his as deep down the other man's throat as he could manage in an effort to dominate this hole as well.

It worked as Fletch opened his mouth as wide as possible to allow Dax's tongue to plunder him freely until he was practically gagging on the thick, supple muscle.

Desperate for completion, the pair twisted and writhed in each other's embrace, no space left between them until it was hard to tell where one man began and the other ended to form the perfect breeding machine.

Finally, Dax lifted his head and came with a roar, grip on his mate tightening as, together, they convulsed and twitched through their shared orgasm. The stud's huge, swollen balls spasmed and flexed for a straight minute as they emptied their load into Fletch's synthetic pussy, forcing the he-bitch's belly to bloat visibly with the sheer volume of seed.

In the aftermath of his orgasm Dax looked down into Fletch's dazed face, gape-mouthed and panting with pleasure, and wanted more. Intent on just that, the stud began to thrust again, his own seed sloshing hotly around his cock in Fletch's belly as he sought to fill it further.

~~~

"How're our prize breeders doing?" Agent Alpha asked a year later as he approached the observation room window where Delta sat at his station.

"Thriving, as always," the other agent answered and Alpha pretended not to notice Delta quickly tucking his still-erect dick back into his pants.

He could hardly chastise the man-- not without getting accusations thrown right back at him, anyways. As long as everyone got their work done (and cleaned up after) Alpha turned a blind eye to his fellow agents getting off to the unrelenting show of animalistic coupling they were forced to observe day in and day out.

"We've got our broodmare down to a one month gestation cycle so he's due in a few days," Delta explained and Alpha released a low whistle, impressed.

He'd been working on some other projects-- trying and failing to secure more breeders as prolific and well suited to churning out new genetically enhanced soldiers at the rate Dax and Fletch did, but they'd yet to even come close. Apparently generating such a well-matched breeding pair had been a stroke of luck not easily replicated.

In the room on the other side of the window, Fletch definitely looked ready to pop, but that wasn't stopping Dax from fucking him with his usual relentless brutality the moment they were put in a room together. At first they'd tried keeping them separated once they were sure Fletch was pregnant with their first specimen but Dax had gone feral at their separation and none of the other broodmares were able to keep up with him for the hours long breeding sessions he required daily.

Well, it hadn't affected Fletch's ability to carry their offspring to term as yet, and those terms were getting shorter with every baby he pushed out so they'd let them be.

"We sure he's just carrying the one pup?" Alpha asked, grinding reflexively against the back of the chair next to Delta's to help ease his arousal at the sight of Fletch, so enormously pregnant his belly pressed into the floor as he crouched on his hands and knees while Dax mounted him from behind doggy style.

"Pretty sure, but not positive," Delta confessed, his own hand going to the front of his pants to rub himself subtly, carrying on what he'd been doing before his fellow agent arrived. "Can be hard getting clear readings through that syn-flesh womb of his. Could be twins."

~~~

Completely oblivious to the men watching them copulate, Dax and Fletch came with a great cacophony of grunts and moans as the ecstasy of release flooded through their bodies simultaneously. Occupied as Fletch's womb was with their latest offspring, though, they massive volume of Dax's seed was forced out in a hot gush around the base of his cock to soak the floor beneath them.

Bliss. It was pure bliss fucking his pregnant bitch and, obsessed as ever with Fletch's body, Dax reached down to grope his mate's fat tit until milk gushed out with one hand and stroked the taut surface of his swollen belly with the other in passionate adoration for the changes he'd forced on the other man.

"Beautiful," he mumbled and began to thrust once more while still milking and petting his favorite broodmare-- eager to feel his cunt tighten with contractions around his massive shaft as a pleasurable prelude to getting to impregnate him once more. "So fucking beautiful."