It's Just Sex Pt. 01

It's Just Sex

by Pan

Note: All characters depicted in sexual situations are over 18.

Chapter 1

Justine's eyes shot open when she walked into the living room to find her youngest daughter on all fours, grunting loudly as her son pounded away at her upraised ass.

Both of them were naked, and both of them had looks of absolute bliss on their faces. Justine didn't even realize she was shouting until the words came out of her mouth.

"What the hell are you two doing!?"

It was a stupid question. It was obvious what they were doing.

Her children stopped immediately.

"Mom??" Isabella said, a look of concern on her face.

"What's wrong?" Terry asked, pulling his cock out of his older sister's ass. "You okay?"

"You two are... you're..."

Lost for words, Justine just gestured at the two naked teenagers. One year apart, Terry and Isabella had always been very close.

Closer than she'd realized, apparently.

Her kids shot each other a puzzled look.

"What?" Terry asked, and the confusion in his voice sounded genuine. "What's the problem?"

"You're... siblings!"

"Yeah..." Isabella said, turning her body to face her mother. The movement made her big tits sway, which caught the attention of both Justine and her son.

She closed her eyes. She shouldn't be looking at her children that way. No one should be looking at their own daughter that way!

"Siblings shouldn't be doing what you're doing!"

Closing her eyes was a bad idea, she quickly realized, because it was too easy to visualize what they had been doing. Terry's long, thick cock pumping into her daughter's butthole, making her scream and moan as her big boobs jiggled from the force of his thrusts...

Justine shook her head, and--almost in a panic--opened her eyes, to see her two youngest children looking at her like she was insane.

"Mom," Terry said. "It's just sex."

"He's right," Isabella said, nodding along with her brother. Again, the movement caused her big tits to jiggle... and again, Justine couldn't help but notice when they did. "We're not doing anything wrong."

"What the fuck are you talking about?" Justine screamed, completely losing her cool. "You two are grounded! Go to your rooms--now!!"

Again, her children exchanged a puzzled look.

"But... we're not finished," Isabella said, as if that was a completely reasonable response to what her mother had just said.

"I don't care!" Justine yelled, on the brink of tears. "Get out of my sight, now!!"

Reluctant and confused, the two teenagers stood up. Justine's eyes widened at the sight of Terry's big, throbbing dick, and she quickly turned away.

She listened to them leave, made sure she heard the sound of two doors closing, then sat down on the couch, her mind racing.

Being a single mother hadn't been easy. She'd been a widow since Terry was five years old. Her oldest, Laura, had been ten when her father died.

Laura had handled it with the sort of quiet strength that had come to define her. She was the best daughter a single mother could hope for, and it sometimes felt like Laura was the only one of her kids who truly remembered her father; to the younger pair, he was little more than a faint memory.

Justine let out a sob. She'd worked so hard to make sure her family stayed close, and to try and keep her children on the right track. She'd done her best to be a good mother. To be a good parent.

So how had it come to this?

She'd never felt so much despair... never felt so much like a failure. How could she have let this happen? How had this happened?

And worst of all... why had her children treated it like it was normal? Like she was the weird one for stopping them from... from stopping them from...

A few tears rolled down her cheeks.

What had Terry said?

It's just sex.

He'd been popular since he'd hit eighteen, and grown into a tall, athletic young man, and Justine wasn't stupid, she knew he was having sex.

But... with his own sister?!

She couldn't stop picturing Terry's big, thick cock pounding away at Isabella's ass. The image of them rutting like animals was seared into her brain. It was wrong. It was so wrong.

It wasn't... it wasn't just sex.

It was sex with a sibling. Sex with a blood relative. That was wrong, and taboo, and... and perverse...

Biologically, yes, Terry was right. It was just sex. When her son had been thrusting inside Isabella, her daughter's huge breasts bouncing, his hardness swelling inside her... on a purely physical level, it could have been any woman and any man. Their bodies had been doing what their biology had dictated.

But humans were more than just biology. Morality, culture, religion, they all told Justine that what she'd walked in on had been so, so wrong.

What the hell had she done to raise her children to believe it was... that it was...

It was just sex.

Justine had calmed down a little bit by dinner. She had decided to divide and conquer; first, she'd talk to her youngest daughter, and when she'd managed to force Isabella to come to her senses, she'd deal with Terry.

No one said much at the meal. Her two younger children just kept looking at her like she'd gone crazy, and if Laura had sensed the tension in the air, she didn't say anything. Justine didn't have much of an appetite, but she forced down her dinner, and then asked Isabella to join her in her room as soon as she had finished.

"Isabella," Justine began, taking her daughter's plate and stacking it with hers. "We need to have a talk. About what I... what I saw."

Justine's youngest daughter was nineteen years old. Her hair was blonde, like her older sister, and she usually wore it in a ponytail. She had an absolutely beautiful face (especially when she put on a light dusting of makeup, as she had that day) and a body that she'd inherited from her mother, with big breasts, a round ass and a narrow waist that made her look very curvy. Every time she stepped out in public, men would be tripping over each other trying to impress her, and Justine had made sure that from the moment she'd started developing, Isabella knew how to set and maintain boundaries with lustful men.

She hadn't wanted her making mistakes that she would come to regret.

Justine's throat went dry as an image of Isabella's naked, shapely body, with her son's cock thrusting inside of it, popped into her head.

She'd fucked up. She didn't know how, but she'd fucked up... and she had to fix it.

"Okay, Mom," Isabella said, sounding less than enthusiastic. It was a tone of voice she only ever used when her mother was about to lecture her.

"Isa..."

Justine didn't even know where to start, but after a moment of hesitation, she forced the words out.

"Is this the first time you and Terry have... done anything?"

"Uh, no," Isabella said, looking mildly embarrassed, but not at all like she'd done anything wrong. "We've, uh, we've been..."

"How many times?!" Justine snapped, before her daughter could finish her sentence.

There was a pause, while Isabella counted.

"A few times a week," she finally said. "For... I dunno, seven months now?"

Justine's head fell into her hands. Her children had been... had been having sex for seven whole months. And she'd had no idea.

"Mom, what's wrong?" Isabella asked. She sounded concerned. "You seem... upset. " Of course I'm upset! Justine thought, angrily. I just found out you've been fucking your brother for the better part of a year!

But instead of saying that, she just took a few deep breaths, until she was calm enough to string a sentence together.

"Sweetie," Justine began, as soon as she was able. "What you're doing is wrong."

"What am I doing?"

"Fucking your brother!"

"Why is that wrong?" Isabella asked, still not showing the least bit of remorse or shame. It was like she genuinely didn't understand why what she was doing was wrong.

"It's... incest!" Justine said, unable to keep the exasperation from her voice. "It's... it's immoral! It's taboo! It's... perverse!"

"Mom," Isabella said. "It's just sex."

Justine reeled at the casual way her daughter said those words, as if it really was no big deal.

As if it really was... just sex.

It's just sex.

"You've been fucking your brother for seven months!" Justine yelled, pushing her confusion down, lashing out before she could stop herself. "And you don't think there's anything wrong with that?"

Isabella just stared at her, looking completely bewildered.

"No?" she said, without hesitation."It's just sex."

Justine stood up, unable to contain herself, and started to pace back and forth. "It is NOT just sex!"

She turned to see that her daughter was staring at her, looking even more confused. Isabella took a deep breath, and spoke slowly, as if dealing with her grandpa when he needed tech support.

"Mom," Isabella said. "Why don't you explain to me exactly what's upsetting you?"

Justine stopped pacing and stared at her, and, against her better judgement, started talking. "You've been fucking Terry for seven months, and that's wrong on so many levels. He's your brother, and siblings shouldn't have sex. AND you've been lying to me for seven whole months..."

"I've never lied to you?" Isabella said.

"You should have told me!"

"You're really upset by this," Isabella said. She hesitated, then continued: "You're not acting like you, mom.

Justine stared at her daughter, completely dumbfounded. She wasn't acting like herself? Her daughter was the one committing a literal crime--several times a week!--and she was the one acting out of character?

"Isabella, what the hell has gotten into you?" she demanded. "I can't believe you've become this... this pervert!"

Isabella winced. "Mom," she said, and her tone made it clear that she was hurt by Justine's choice of words. "It's just sex."

Justine took a moment to compose herself, and when she spoke again, it was in a calmer, less judgemental voice. "Isa," she said, reaching across the table and taking her daughter's hands in her own. "You have to understand that what you're doing is wrong. I love you, and I want you to be a good girl. You can't keep having sex with your brother."

Isabella looked down at their joined hands, then up at her mother, her eyes full of hurt.

"But... we both like it. It feels really good, and it's not like we're hurting anyone. It's... just sex."

It's just sex, Justine's mind echoed.

For a moment, Justine forgot that what Isabella had done was wrong. For a moment, the statement sounded completely reasonable.

It was just sex. It was just two young, attractive people doing what young, attractive people had done since the beginning of time.

Again, the image flashed into Justine's mind: her son's long, thick cock, pounding into her daughter's ass, her huge breasts swaying as he fucked her...

Justine blinked, shaking her head.

"Isa," Justine said. "I don't want you having sex with your brother. Do you understand me?"

"I... I understand that's what you want," her daughter said, and Justine's eyes narrowed.

"Sweetheart," she said. "I know you're young and inexperienced, so it's okay that you don't understand. But you're going to thank me one day, when I've stopped you from ruining your life."

Isabella looked down, avoiding her mother's gaze. She looked like she wanted to argue, but wasn't willing to say anything.

Justine sighed. This was a disaster. How the hell had this happened?

"Isabella," Justine said, forcing her voice to stay calm."I don't want to find you and your brother... together, ever again. Understand me?"

Isabella didn't look up, and Justine wasn't sure if that was because she was still upset, or because she wasn't willing to go along with it. But she said: "I understand, Mom," and that was enough for Justine.

For now.

"Now go to your room," the older woman said, her voice shaking. "We're done here."

Her daughter stood up and left without another word. As soon as she was alone, Justine broke down in tears.

It was too easy to imagine how it had started. Terry and Isabella, the closest pair of siblings Justine knew. Justine's youngest daughter had always had her big brother to protect her from bullies, and Terry had had his baby sister to dote on. The pair had been attached at the hip for the first few years of Isabella's life, and while they'd had a bit of a falling out when she hit puberty, it hadn't taken long for them to rekindle their closeness.

It had been a point of pride for Justine, that all three of her children got along. They'd never fought, not like other siblings, and they'd all been close with their mother.

She'd never known that her daughter and son were close in that way. Had Terry been the first to initiate, or had Isabella?

The way they spoke about it, it might have been mutual. Neither of them seemed to find anything unusual in using each other's bodies for pleasure. For mutual satisfaction.

How had Isabella put it?

"We both like it."

It was wrong. So, so wrong. They were blood relatives.

But there was a kernel of truth to her daughter's words. If they both liked it, if Terry hadn't forced his little sister into sex, then was it really that wrong?

After all, it was just sex.

No!

No. She had to stop thinking that way. She had to stop them.

She had to stop them.

Justine wiped the tears out of her eyes. She had to make sure that Terry and Isabella understood that what they were doing was wrong. To protect each other, to protect their family.

It was her responsibility.

With a shuddering sigh, Justine went to the bathroom to compose herself. When she was done, she made her way to Terry's room, trying to work out what exactly she was going to say.

"Terry," she called, and took the noise she head from behind the door as an invitation.

But when she entered, it was obvious that Terry and his older sister hadn't heard her.

They were otherwise occupied.

Terry was naked again, laying on his bed, while Laura was on top of him, wearing only a t-shirt. Neither of them were facing the door, and they didn't even seem to notice Justine enter. She could see her daughter's ass, and the way it bounced when she drove her cunt down on Terry's huge cock. Her huge tits were swinging, much as Isabella's had been earlier that day, and her fists were clenching again and again as she rode his dick. Laura was moaning and whimpering, like she was in heaven, while Terry's fingers were digging into her hips, holding on as he was ridden.

"Oh, fuck!" Laura cried out, and Terry gave a guttural moan in response.

"Fuck," Terry groaned, thrusting his hips up into his sister's cunt, making her whole body bounce, her tits jiggling as her ass landed in his lap.

Justine was frozen in place, her eyes darting around, capturing a thousand details she never thought she'd see--or want to see! Laura's pussy lips were stretched around her brother's thick shaft, and her body was trembling every time she took him to the base.

"Laura," she said, but neither of them reacted.

Terry grunted again, thrusting harder into his older sister. "Oh, fuck!" Laura cried. "Fuck me, baby, just like that! I'm gonna... I'm gonna... I'm gonna cum! Oh, god, I'm gonna fucking cum!"

"Laura!" Justine said again, but the room was filled with her daughter's screams as her whole body shook. She came, in the loudest, longest orgasm Justine had ever witnessed. Her oldest daughter was shaking from head to toe, her huge tits bouncing and swaying as her pussy clenched down on her brother's cock, and she screamed again and again.

"Laura!" Justine screamed. "Get off your brother's dick, right now!!"

Laura looked up, her face a mask of ecstasy, clearly seeing her mother but not registering her. She didn't move to stop, continuing to bounce on her little brother's dick, but Terry finally seemed to realize that his mother was in the room.

"Mom?" he asked, in a tone of voice that suggested he wasn't happy to be interrupted twice in one day.

"Get the fuck off of him, Laura!"

Laura looked like she was past the point of comprehension, but with a strength and delicacy Justine hadn't expected from her son, Terry picked his older sister up and lifted her off his cock. She made a strangled sound as her pussy slid free from his length, and Justine's jaw dropped at the size of her son's penis.

She'd seen it earlier, when Terry had been deep in his sister's ass, but she hadn't realized how huge her son's cock was. It glistened with his older sister's juices, and was throbbing and twitching as Laura's naked cunt came to rest on the bed.

"What do you need, Mom?" Terry asked, and Justine realized she was staring at his huge horse cock, his balls the size of kiwifruit, and that she'd been doing so for at least ten full seconds.

She looked up at his face, but it was impossible not to imagine his cock as she did. She'd never seen a cock that big in real life--and her husband had been very well endowed. But Terry's cock was thicker, longer...

Justine shook her head. That wasn't why she was here.

Well, actually... that was exactly why she was there.

"What the hell are you two doing?" she yelled, not bothering to hide the panic and confusion in her voice.

"Sex," Laura said, her voice slurred, like she was drunk.

Justine's mind flashed back to her conversation with Isabella.

It's just sex.

Her younger daughter had said they both liked it. And if her experience had been anything like Laura's, Isabella hadn't been lying. Both of them had been screaming, like nothing else mattered, like the only thing in the world that existed was the cock that had been inside of them.

The cock that belonged to their brother.

It was wrong. Right? It was absolutely wrong, to have your brother's cock in your pussy. Or ass. Right?

She looked at Terry, at the way he was still gripping his sister's naked hips, his huge cock throbbing against her skin. Laura's tits were only slightly smaller than her sister's, and they were flushed and red from the orgasm she'd had.

From the orgasm it looked like she was still coming down from.

"What's wrong, Mom?" Terry asked, his voice a mix of concern and impatient.

Twice, now, his mother had interrupted his orgasm. Twice, now--in the same day!--she'd stopped him from cumming inside his sister's tight little pussy. Or ass.

Justine was not an idiot, and she was not naive. She knew exactly why Terry was upset. She'd have been surprised if he hadn't been upset.

But that didn't mean he had the right to fuck his sisters. Both of his sisters!

"You can't do this," she gasped.

Laura looked at her with a look of sleepy confusion on her face, still coming down from her orgasm. "Do what?"

"Fuck your brother!" Justine snapped.

Why not?"

"It's wrong!" Justine said, her head thick with confusion and disbelief. "It's incest! It's immoral, and perverse! It's illegal!"

She'd said the exact same thing to Isabella, and she'd gotten nowhere. She was starting to worry she was going crazy, or that her kids already had. How were they not understanding this??

"It's just sex," Terry said, and Justine stepped backwards as if she'd just been slapped.

It was just sex.

Just sex.

Looking at her twenty-four-year-old daughter, she could fully understand where they were coming from. Laura's face wasn't one of an abused woman, of a sibling whose brother was taking advantage of her.

She looked like a young woman who'd just had the best sex of her life. Better, Justine could admit, than any sex she herself had ever had.

Yes, it was with her brother. But so what? It was... it was just sex.

No!

"It's not just sex!" Justine said, through gritted teeth.

"Why not?" Laura asked, and Justine struggled to answer.

Why was she so bothered by this?

Why did this feel so wrong? Her son had been fucking his sisters for the better part of a year--Isabella, at least, and who knew how long Laura had been in on the action--and they didn't seem to mind it. Their grades hadn't suffered, their family was closer than ever. No one was unhappy, no one was being coerced. They were all consenting adults, and their bodies were their own, to do with as they pleased.

And this seemed to please them very much, if Isabella's moaning and panting and grunting was anything to go by. And Laura's screams of ecstasy spoke for themselves.

Screamed for themselves, even. It was just sex. It was just a young man and two young women, all consenting adults, having the best sex of their lives.

They just happened to be sister and brother and sister.

But it was just sex.

Justine took a deep, calming breath. She was letting her emotions get the best of her. She had to be rational, she had to be reasonable. She had to think.

"Look," Justine said, taking another breath. "I know this seems fun and exciting and... and new, but it's not right."

"It's not new," Laura said. She seemed to be coming back to her senses. "We've been fucking for months."

"How long?"

"Six months?" Laura looked at Terry, as if for confirmation, and he nodded.

"Six months," Laura said. "Since I walked in on Terry and Isa fucking. I thought it was weird at first, but once I tried it..."

Terry smiled at his sister, and Justine's eyes were immediately drawn to his big dick, which was still hard, and still completely uncovered.

"And frankly, Mom... it's been the best six months of my life."

Justine nodded. From what she'd witnessed, she believed her daughter.

But that didn't make it right.

"It's immoral," she said again, and both her kids looked like she'd just spoken a different language. "It's illegal."

Laura shrugged. "So was weed," she said, "but Aunt Melissa smokes that, and you never cared."

Justine blinked. "That isn't hurting anyone," she replied. "But incest..."

"It's just sex," Terry said, and the older woman couldn't stop her eyes from being drawn back to her son's big, thick dick. He noticed her gaze, and his cock twitched, swelling up and making her gasp. "It feels good, and we both like it."

Justine nodded. It made sense. Sex was a perfectly natural act, after all. Humans had evolved to do it, to continue the species. It made sense that an attractive young man, surrounded by women, would... would...

"Mom, are you... are you okay?" Laura asked. "You seem upset. You're not acting like yourself."

Justine looked into her daughter's eyes.

"I'm just worried," she said, her voice a whimper. "This isn't normal, what you're doing. What all of you are doing."

"Since when do you care about normal?" Terry asked, raising one eyebrow. "You raised us to think for ourselves and to be our own people."

It's not a crime to be a little bit different, Justine, her own mother had told her, years earlier. She hadn't meant for her to apply that to the present circumstances, but... was she wrong? Justine had raised her kids to think independently, to not follow the crowd, to not do things just because they were expected to. So why was she trying so hard to make them conform?

"If anyone found out, they'd lock you away," Justine said quietly, as if she didn't even believe herself.

Laura laughed, as if that was a ridiculous argument. "That's a stupid reason not to do anything," she said.

"No one needs to find out, Mom," Terry added. "We can keep this a secret. You didn't even know until today."

He was right, and Justine knew that he was right. If she hadn't walked in on her children--twice--she'd have never suspected that anything was happening. All three of them could keep a secret.

And what was the harm, really? She felt like an old fogey, living in the past. No, in her day, siblings hadn't had sex. But they also hadn't had the internet. They hadn't been as open to experimentation, and they hadn't had as many opportunities to learn new things.

They certainly hadn't had as much access to porn. She was sure that was what had started this. All that step-sibling porn... it must made them think it was normal, and they'd decided to try it out, and realized how much fun it was. And it did look like fun. Like a whole hell of a lot of fun...

"Mom," Laura said, her voice soothing. "I know it seems weird to you, but it's just sex. We really like what we're doing. It makes me feel so good to have sex with Terry, and I know he likes it too. It makes me feel like a woman."

Again, Justine found herself nodding. What was more womanly than-... than being fucked? What could make a girl feel more feminine than to take a strong man's big, thick cock up her cunt, up her ass, into her mouth. To make him cum.

"And no one is being hurt," Laura continued. "No one is going to find out."

Justine looked at her daughter, and saw nothing but honesty and compassion in her eyes. Her face was completely clear of shame or embarrassment. It was clear that she completely believed what she was saying, that she truly thought that incest was no big deal, as long as everyone was enjoying it.

Justine's eyes moved to Terry, who had the same look on his face.

"It's just sex," he said again, and Justine found herself nodding.

"It's just sex," she said.

Chapter 2

Justine didn't sleep that night. She just stared at the ceiling, replaying what had happened over and over in her mind.

Sex was a biological function, and siblings were just as sexually compatible as any other pairing of men and women. Moreso, in the case of her own children, from what she'd seen. The way Laura had screamed, and twitched, the way her whole body had shaken with pleasure...

And Terry's big cock... no wonder both the girls had fallen for him. He was surrounded by two busty, horny women, and he was packing a piece like that? It was almost inevitable that something was going to happen.

But still. Six months... seven, for Isabella.

A total of thirteen months of incest, happening under her own roof.

It felt wrong. Yes, it was just sex, but Justine still couldn't shake the thought that there was something perverse about it. Something... sinful.

She and her sister had been raised religiously, but she hadn't really thought about it since her husband had died. She hadn't consciously tied the death of her husband to the death of her faith, but as time had passed, Justine had grown further and further away from God.

Now, lying in bed, she found herself thinking about the religion of her childhood. She'd always been taught that sex before marriage was a sin, that only married couples were allowed to enjoy the pleasures of the flesh.

But that had never made sense to her, and she'd lost her virginity at eighteen, in her own bedroom, with her high school sweetheart. They'd dated for a year before that happened, and she'd never once felt bad about it. She'd always been a sexual creature, and she'd always enjoyed sex.

And that was back in the days of VCRs and the internet was in its infancy, when porn was still something you had to seek out. She'd done what she was taught was 'sinful', and pornography had nothing to do with it.

Her children had grown up in an age where sex was everywhere, where every movie and TV show was filled with it, and where porn was a click away, at all times. It was easy to point to that as the cause of their behavior, but... had it really been that?

Had they really fallen into bed with each other, just because they'd watched a few too many incest porn videos? No. That was ridiculous. The internet hadn't been the cause of Terry and Isabella starting to fuck.

They'd fucked because they'd wanted to fuck. It was just sex.

Just sex.

Justine groaned. Why did she care so much? It wasn't like anyone was going to get knocked up. She'd gotten both her daughters on the pill as soon as their bodies had matured, and she trusted that Terry was clean.

No one was getting pregnant, no one was getting hurt, and the whole thing was a secret.. There was absolutely no harm in this.

It was just sex.

Justine sighed. No matter how hard she tried, she couldn't escape that phrase. The more she tried not to think about it, the more she kept thinking it.

It's just sex.

How many times had she heard that in the last twenty-four hours? Her children had said it, and she'd repeated it, and she was repeating it in her head, over and over, as if trying to convince herself.

Because it wasn't just sex. It was incest, it was immoral, it was perverse, it was illegal, it was wrong, it was...

... it was just sex.

It was just sex.

After hours of tossing and turning and running the thoughts through her head again and again, Justine finally drifted off to sleep. She slept fitfully, but she did sleep, and in the morning, she felt a tiny bit more calm.

"Good morning," Justine said, as she came into the kitchen. Isabella and Laura were talking, and Terry was finishing breakfast for all of them. They all smiled as they turned to look at her, and she smiled back, and it felt... normal.

No wonder she hadn't picked up on anything happening. To talk to them, you would never know that Terry's huge cock was spending time, every day, in his sister's asses and pussies and... had Laura said mouths?

Justine had never particularly enjoyed giving head, but it was impossible to stop herself from imagining what a cock the size of Terry's would feel, pushing past her lips, sliding down her throat.

It was impossible not to imagine how satisfying it would feel to get a beast like that off. To feel those huge balls of his pulsate, shooting load after load of hot, sticky cum into her hair, her face, onto her enormous chest...

She shivered, and sat down to breakfast, and everything was normal.

It was all so, so normal.

She was sitting next to her son, whose penis she had seen, and who was fucking both of his sisters.

She was eating breakfast with her children, all three of them, and the two girls were both getting fucked by their brother, and all three of them seemed to think that it was no big deal. Like it really was... just sex.

Most of the day passed as normal. It was school holidays, and Justine had taken a week off work to spend with her family. Perhaps that was why she'd finally caught them--not that it seemed they'd been trying to hide their activities.

She noticed Terry and Laura both make an excuse to leave within a few minutes of each other. She'd never have noticed that sort of behavior before, but now, it was obvious what they were doing. It was all too easy to imagine them both in his bedroom, completely naked and rutting like animals.

Justine and her youngest daughter were left alone, and the forty-five year old woman's heart melted when Isabella shot her a look.

"You doing okay, mom?"

"I'm fine, honey."

Isabella didn't seem to believe her. "You sure? Because... I mean, yesterday you really seemed upset."

Justine looked at her daughter. She was wearing a light summer dress, and--since it was just with family around the house--had clearly chosen to go without underwear. The shape of her nipples could be seen against the fabric of her dress, and Justine had noticed a slight cameltoe when her daughter had crossed and uncrossed her legs a minute earlier. She'd never have noticed something like that before, but now, it felt like she was hyper-aware of what was happening in her house.

Isabella's blonde hair hung loose, and her blue eyes were filled with love and compassion. Justine sighed, and found herself asking the question that had been on her mind all day.

"How did this happen?"

"Um..." Isabella said, looking uncomfortable for the first time since her mother had walked in on her and Terry the previous afternoon. "Well..."

She was silent for a moment, then spoke. "Do you really want to know, mom? I don't want to make you uncomfortable."

"I really want to know," Justine said softly. I need to know, she told herself.

"Well, it was Christmas," Isabella said, a smile on her face. "Terry had just turned nineteen, and I'd just turned eighteen, and we were hanging out in my room, watching movies, when Terry suggested we put on some porn."

Justine's eyebrows shot up.

"I know," Isabella laughed. "I had the exact same reaction. I told him that he was disgusting, and to get out, but he said..."

For a moment, a wrinkle appeared on Isabella's face, like she'd remembered something, but then she shook her head. "He said that it was just sex."

Justine nodded. That made sense. It was still shocking that her polite, respectful son would try to watch porn with his little sister... but they'd already been watching movies. And sex was, ultimately, a normal part of life. Not with your siblings, no, but... everyone did it. Justine did it. Her children did it.

It was just sex. And a porn flick was just a movie about sex.

"I told him to get out, but he apologized and said that I could choose. He'd watch whatever I wanted to watch. And..." Isabella's cheeks blushed a light red. "The more I thought about it, the more I realized he was right. It's just sex."

It's just sex.

"Right," Justine said. "It's just sex."

"Exactly. So I said fine, we'll watch porn... but we're going to watch the kind of porn I want to watch. And Terry was happy with that."

"And what kind of porn do you like?" Justine asked hesitantly, before realizing she had no reason to be embarrassed. It was just sex.

Isabella smiled. "Girl on girl stuff, mostly."

"Really?" Justine asked, tilting her head to the side. Isabella shot her a look like she was an idiot.

"Yeah. You... you know I'm gay, right?"

Justine reeled. How had she become so disconnected from her children? They were having sex (with each other!) and Isabella was... Isabella was gay.

Wait.

"But... you and Terry..."

"Oh, that," her (apparently lesbian) daughter laughed. "I mean, I'm not in love with him. It's just sex."

It's just sex.

Justine nodded. She wasn't gay--she'd never had any interest in other women--so she couldn't pretend to understand. But if her LGBT daughter said that was part of being a lesbian, she had to believe her.

"So we put on a few videos of hot chicks going at it," Isabella continued, "and I got super horny."

The middle-aged mom nodded again, and Isabella continued: "And I wanted Terry to leave, because... well, I wanted to do what you'd expect, but he just kept telling me that it was normal, and natural, and that it was okay for him to be there. That it was just sex. It's just sex."

"It's just sex."

"Right. Eventually, I gave in," Isabella said, with a shrug. "I couldn't focus on the movie anyway, and Terry was totally right, and... and I was so horny, so I started to masturbate. I kept my dress on, but slipped my hand under it, and played with myself while Terry watched. It felt so good... I mean, it's masturbation, so yeah. That's what you'd expect. But Terry being there wasn't even a factor."

"It's just sex," Justine said under her breath, and Isabella nodded.

"I don't remember if he was the one to suggest it or if I did, but... well, since I was horny, and he was clearly horny...--"

"How did you know he was horny?" Justine interrupted, and her daughter--for the hundredth time that day, it felt like, looked at her like she was an idiot.

"It's, uh, it's pretty hard to miss."

"Right," Justine said, feeling her face go red.

"So..." Isabella shrugged. "We had sex."

She made it sound like it was no big deal. Like it was... like it was just sex.

"It was amazing," her daughter continued. "Terry's huge, and even though it was my first time with a dick, I came the hardest I ever have."

Isabella had a look on her face that was all bliss. Justine couldn't blame her. She'd seen her son's dick, and she could only imagine how good it would feel inside her.

"He fucked me, and I rode him, and he took me from behind, and I sucked his cock," Isabella said, and she bit her lip at the memories. It was clear that she wished she was with Terry right at that moment. "He came inside me, again and again, and it felt so good. We must have fucked all night."

A memory suddenly flashed into Justine's memory--the day that her two youngest children had come down with unruly hair and bags under their eyes. They'd told her they hadn't slept a wink, and she'd just assumed... she'd assumed...

But no. It was obvious now. They'd been up all night fucking, and they'd come down to breakfast, the day after Christmas, and she hadn't had a clue. She'd thought they'd stayed up playing video games, or something. She hadn't even considered that the two siblings might have been in bed together.

"And the more we did it, the better it felt," Isabella said, her voice dreamy. "I love his cock, and he loves my body, and... it's just sex, but it feels so good. The first time he fucked my ass, I screamed so loud, I couldn't talk the next day."

Isabella smiled at the memory, and Justine felt a pang of jealousy. But... no. She couldn't be jealous of her daughter for having sex with her son.

It was wrong.

Right?

Or was it... just sex.

Was it really that big of a deal? They weren't in love, they weren't dating, they weren't even the same sexual orientation. Isabella was gay, but that didn't matter. It was just sex. What did it matter if they were siblings? Who cared if they were related by blood? If they both enjoyed the experience, and they both liked it...

"Mom?" Isabella said.

"Huh?"

"What are you thinking about?" Justine looked at her daughter, who was sitting across from her, her nipples poking out from behind her thin summer dress.

"I'm thinking that... that it's just sex."

Isabella smiled, and it was like a weight had lifted off her shoulders. "Exactly," she said. "It's just sex. It's just a way for me and Terry to blow off steam, and have some fun, and get a little bit of practice."

"Practice?" Justine asked, one eyebrow raised.

"Well," Isabella said with a grin. "You know what I mean."

The older woman smiled. She didn't, but she didn't want to admit that.

"So," she said, changing the topic. "Laura?"

Isabella shrugged, and Justine found her eyes drawn to the movement of her breasts.

"I feel like you should ask her about that," she said.

Justine nodded, and went to stood up. Before she could, Isabella reached out, her hand on her mother's leg. "Mom," she said, and Justine paused. "You said you didn't want to catch us in the act anymore."

"I did?"

Isabella nodded, and Justine suddenly remembered the conversation they'd had the previous night. God, she'd been so worked up about it. No wonder her kids had thought she was acting like a mad woman.

It was just sex.

"Don't worry about that," she replied, before pausing. "But... just to be clear, I didn't just mean I don't want to catch you. I was trying to tell you to stop doing it entirely."

Her statement was met with a laugh, and Justine quickly found herself laughing as well. What sort of a ridiculous edict was that? Telling her children not to have sex anymore was like telling a fish to stop swimming.

"I don't think any of us are going to stop," Isabella said with a giggle. "In fact, I was going to ask..."

Isabella trailed off, and a tinge of pink appeared on her cheeks.

"Ask me what?"

"Would it... would you like to..."

Justine had no idea what her youngest daughter was getting at... until Isabella leaned forward and pressed her lips to her mother's.

The older woman pulled back, completely shocked by her daughter's actions. "Isa," she stammered, but the teenage girl cut her off with another kiss.

And this time, Justine found herself kissing back.

She had no idea why. She knew it was wrong on so many levels, but Isabella's mouth had been so soft, and her tongue had tasted so good, and her lips had been so warm...

It felt so wrong, and it was so wrong. Justine pulled back with a gasp.

"You're my daughter," she said pleadingly.

"It's just sex," Isabella replied, staring her mother in the eyes.

Justine shuddered. Her daughter's words were so...

"I'm not gay," she said, her voice even quieter this time.

"It's not about that," Isabella assured her with a smile. "It's just sex."

It's just sex.

It's just sex.

"It's... just sex," Justine muttered, and her daughter's lips were on hers again. This time, Justine leaned into the kiss, opening her mouth and letting her daughter's tongue slip inside. She wasn't sure if she was moaning or if her daughter was, but the sound of the pleasure they were experiencing filled the air.

"It's just sex," she said, when they finally parted.

"It's just sex," Isabella agreed, and kissed her mother again.

Justine didn't know when her daughter undid her bra, or when her hands moved up her shirt and landed firmly on her mother's huge, round bosom. She had never been more turned on; all of a sudden, all she wanted was for her daughter to play with her body. To squeeze and massage her breasts, to pinch her nipples and roll them in between her fingers, to remove her shirt and bra and suck on them, like she had when she was a babe.

Justine moaned at the thought. Isabella had been such a thirsty baby--perhaps that should have told her that she was a lesbian. And now, after a sixteen-year gap, she was going to get her mouth back on her mother's tits.

She'd never been this horny in her life, and it was her own daughter that was turning her on.

Isabella squeezed her breasts again, and Justine moaned. "Oh, fuck..."

"Does that feel good?" Isabella asked, and the older blonde nodded. She couldn't stand to wait until Isabella took the initiative; Justine took her shirt off. She wanted her daughter's mouth on her nipple. She wanted to feed her again.

"Mom!" Isabella said, as her mother's huge, round breasts were exposed. They were larger than even Laura's: Justine's were the tits of a woman who'd breastfed three children. Justine's were the tits of a mature woman, fully developed, with years of sexual experience under her belt.

Justine's were the tits of a mother who'd just decided to have sex with her own daughter.

Something about that struck Justine as wrong, but she was too turned on to think. It was fine, right? It was just sex. Yes, Isabella was her daughter, and no, Justine wasn't gay... but she was turned on and it was normal to have sex when you were turned on. That was what sex was for, to release tension.

To feel good.

It was just sex.

With a whimper of anticipation, Justine put one hand on the back of her daughter's head and guided it to her breast.

"Come on, baby," Justine breathed. "You used to love this."

Isabella opened her mouth and sucked on her mother's huge, thick nipple, moaning as her tongue touched the older woman's skin. Justine could feel her daughter's warm mouth on her breast, and she could feel her tongue, teasing and licking and sucking her nipple, and Isabella's hand on the other breast, massaging it and pinching the other nipple and making her gasp. It was all too easy to imagine that milk would soon be gushing out, as it had so many years ago, filling her baby girl's mouth and making her moan and suckle harder, her mouth filled with creamy goodness.

Justine was panting. Why had she been so opposed to incest again? She wasn't gay, but this... this wasn't about that.

It was just sex.

"I wanna taste your cunt," Justine gasped, and Isabella's eyes shot up to meet her mother's gaze.

"What did you say?"

"I said," Justine said slowly. "That I want to taste your cunt."

"Where did that come from?"

"I've never done it before," Justine admitted. After her high school boyfriend, she'd only slept with one or two other guys before meeting the father of her children, the love of her life.

And since his passing, she hadn't had anyone.

"Mom..." Isabella breathed. "I can't believe you're being this filthy."

"It's just sex," Justine said, feeling defensive. Her daughter nodded.

"It's just sex," she agreed.

Justine grabbed her daughter's hand and--again, in an action she hadn't done for over a decade--removed her clothing as quickly as she could.

"Fuck," she breathed. "You're so beautiful."

Isabella blushed. "I get that from my mother," she said.

She'd seen her daughter's naked body when she'd been on all fours, Terry's cock deep in her ass--and the dozens of times she'd replayed the scene in her head since then--but now she had time to truly appreciate the sight. Justine let her eyes roam all over Isabella's nude form, from the legs to her stomach, from her back to her arms to her chest, and finally to her face.

Justine's hands moved up Isabella's curves, landing on her breasts and pinching her nipples. Isabella's face was pure bliss, as if this was something she had dreamed of for a long while, and she lay back on the couch and let her mother explore.

"It's just sex," she murmured, as her mother's fingers found their way between her legs. "Just sex."

"Oh, fuck," Justine moaned, her fingers finding her daughter's clitoris. She could see Isabella's little slit, and the way it glistened and gleamed with teenage arousal. Her mouth began to water. "Oh darling. You're so wet..."

"That's also because of my mom," Isabella replied teasingly, and Justine looked up at her affectionately. As her tongue tasted her daughter's cunt for the first time, her eyes fluttered in pleasure. Justine's daughter tasted divine--she had no idea why she hadn't done this sooner, and she had no idea why she'd ever thought it was wrong.

She was addicted, immediately. In moments, she was doing all she could to burrow into her daughter's tight little pussy,. Her tongue was thrusting in and out of her daughter's tight little cunt, flicking the girl's clit, tasting her wetness, and loving every single moment of it.

Isabella's legs wrapped around Justine's neck, holding her in place. She couldn't move away, even if she wanted to. And she definitely didn't want to. She loved the way her daughter was moaning, the way her voice hitched when her tongue found her clit, the way she was whimpering as the pleasure increased.

Isabella's voice rose and rose, and she started to shake and tremble, her whole body spasming as her mother's mouth sent her into orbit.

"Oh, Mom! Oh, fuck! Mom! Mom!!"

Justine hadn't witnessed her younger daughter's orgasm, only Laura's. No wonder her children had been so confused when she'd made them stop--what she'd done, she realized now, had been downright rude. Isabella had been on her way to a mind-blowing orgasm, and she'd gotten in the way. And why?

For absolutely no reason.

It was just sex.

Justine made a mental note to apologize, but for the moment, focused on the task at hand. Her mouth was sucking on her daughter's clit and her fingers had reached up to play with Isabella's huge, perfect tits.

"Mom!" Isabella cried, and Justine's heart swelled with pride as her daughter came, juices spraying over her mother's face. She felt a little foolish for how much she enjoyed knowing she was getting her daughter off--after all, it was just sex.

But the fact was, she wanted to make her daughter explode with bliss, to bring her to the absolute height of pleasure. Her fingers squeezed the girl's breasts, her tongue flicked her clitoris and her lips sucked, her ears listening to the sounds of the teenager's orgasm. It was the most beautiful music Justine had ever heard in her life. Her daughter screamed and cried out and moaned and gasped, her body thrashing about as Justine continued to eat her out.

Finally, Isabella's sounds of pleasure subsided, and the teenager's grip on Justine's head relaxed. The older woman's tongue slowed down, and she pulled back, her daughter's juices smeared all over her face.

"That was... that was amazing," Isabella whispered, and her mother smiled.

"Yeah."

"My turn," Isabella replied, a fire in her eyes. Her hand slid down her mom's pants.

Before Justine could say a word, Isabella's fingers had found what they were looking for, and an involuntary moan came out of the older woman's mouth.

"Isabella!" she gasped, and her daughter's eyes gleamed. Her finger was rubbing her mother's clit, with an expertise Justine had never experienced in her life. It felt like heaven, as the eighteen-year-old girl played with her mother's pussy.

She was so wet, and her daughter was so talented, that it wasn't long before Justine could feel her own climax approaching. Just as her body began to clench, Isabella leaned forward, her mouth meeting her mother's, and Justine realized she must be able to taste her own juices on her lips. Justine moaned as Isabella's tongue entered her mouth, and she came long and loud, her daughter's finger making her shake and spasm. She could feel her daughter's naked breasts pressing against her own, and their tongues were dueling, and her daughter's finger was so skilled...

It was too much for the older woman to take.

By the time her climax subsided, she was sobbing. Isabella pulled away and Justine's mouth opened, to thank her daughter for the orgasm, but all that came out was a whimper.

In response, Isabella just leaned forward and pressed her lips against her mother's again.

Her tongue slipped inside, and Justine found herself sucking on it. She was struggling to think, struggling to process what was going on. All she knew was that her pussy was still aching for more, that her body was begging to be touched, and that she had never felt anything this good before in her life.

Justine's daughter brought her to another orgasm, then another. For what felt like hours, Justine lay there, her body being played with, her pussy being rubbed and massaged, her daughter's fingers exploring the depths of her cunt, being brought to climax over and over and over again, and her daughter's lips on hers, her tongue in her mouth, their bare tits pressed against each other.

Finally, just as Justine thought her brain was going to melt, Isabella pulled back, a look of pride on her face.

"Fuck," Justine breathed. "Isa, that was amazing. You're so good at this. You're going to make some girl very happy one day."

"Thanks," Isabella replied, biting her lip. "But... well, you know."

"It's just sex," the two women said in unison.