Manaka hissed at Ryosuke in a stifled voice, her breath hot against his ear.
"I can't believe you'd do something like this... I... I won't forgive you... Ngh!"
But her hostility was cut short the moment his lips latched onto the nape of her neck.
"Stop! Ah!"
Despite being sweaty, her skin carried a sweet, almost intoxicating scent—the musky aroma of arousal. Her stifled moans only stoked Ryosuke's lust further.
"Fuuu! Ah! Ugh...!"
His right hand kneaded her breasts roughly, leaving them in a sorry state.
Even through her undergarments, her full bust had somehow managed to appear smaller than it actually was. Ryosuke's hands, large even for a man his age, couldn't contain them. The softness was overwhelming, his fingers sinking endlessly into the pliant flesh.
Furthermore, the overly large fruit, now drenched in sweat, had a sharp vulnerability at its tip.
"Did Nii-san do this to you too?"
"Ugh?!"
This time, she glared at me with eyes brimming with fury.
But...
"Hif...?!"
When I gently stroked her nipple with the pad of my thumb, she arched her back and groaned in torment.
Apparently, she hadn't received any proper affection. All she'd ever known was the rough pleasure of her breasts being squeezed roughly or her nipple being jabbed—probably even today.
"You were doing it again today, weren't you? How could you, Nee-san? Have you any idea how I felt waiting for you?"
"!"
I hadn't really thought about it, but my words seemed to have an effect.
"Doing... this kind of thing..."
"Hmm?"
"You always do this kind of thing to girls, don't you...?"
It seemed Manaka was trying to change the situation through conversation. Her intentions were obvious, but Ryosuke decided to play along.
"Me? I've never done anything like this before. Nee-san was the one who started everything."
Ryosuke answered honestly.
But it seemed she didn't believe him. Manaka's expression hardened.
"Don't be ridiculous! And you should definitely—"
"Haha. Feeling your nipple while giving me a lecture?"
His mocking laughter made Manaka's face flush even redder with humiliation. But by now, she couldn't resist even a single finger from Ryosuke. Just gently tracing the edge of her left nipple with his fingertip was enough to make her squirm.
"Ah! Ah—stop!"
Her body betrayed her desires, making it clear where she wanted to be touched.
Ryosuke had always been good at sensing what others wanted. He possessed average knowledge of sexual techniques, but he never imagined they would align so perfectly in practice.
...Then what about this?
"Ah! N-no, Ryosuke, stop there! This isn't a joke anymore!"
Deep beneath Manaka's summer skirt, her panties were damp. Was the moisture on the underwear covering her soft flesh, different from her breasts, really just sweat?
"I never intended this to be a joke. You were the one who invited me, right, Nee-san?"
If Manaka wanted to become his "family," that was fine with him. No one had ever wanted that before, so he couldn't even imagine what it would be like to have a "sister."
...What was I expecting?
But Manaka was a woman. Not only had she brought her lover here to engage in sex, but she had also flaunted her body to Ryosuke.
I wasn't shocked. Even if I had harbored expectations, they were purely observational. I've never trusted anyone but myself, so there was no great disappointment.
Therefore.
If my older sister-in-law wants to be a woman—no, if this woman wants to be a bitch, I'll grant her wish.
"I'll let you do what you've always wanted, Nee-san."
Jug...
I pressed my thumb against her crotch through the fabric, feeling the dampness of her flesh even through the cloth. I could even feel the shape of her folds.
"Ah—?!"
"You were doing this with your brother just now, weren't you? Then you can do it with me too."
"N-Nii-san... Ryosuke..."
"Let's have sex, Nee-san."
Oh no... he's going to violate me...! I can't let Ryosuke—!
As her womanhood was toyed with, the reality of the situation she'd feared so much suddenly loomed before her.
His fingers, though clearly aroused, moved with unnerving calmness.
Despite her drenched state, the fabric of her soaked panties now barely serving as a barrier, his touch traced the shape of her labia, moving up and down. Then, with a crude precision, he found her clitoris, making it stiffen shamelessly.
"Ah—!"
"Is this spot weak too? Just a little thrust and you're already arching your hips. Nee-san, do you realize how embarrassing your body is?"
"~~~~..."
She glared back at Ryosuke, but even she couldn't believe she still carried any dignity as an older sister, with both hands clamped over her mouth to suppress her moans.
Sister.
Had she ever really believed she was a sister? She'd certainly thought so when she was trying to bring Ryosuke and Marin closer. But then where did it go wrong?
It started after I had sex with Takuma.
From that moment on, I became acutely aware of my own femininity. Being intimate with Takuma was utterly irresistible. It wasn't just physical desire; I found myself genuinely craving a man's touch from the depths of my heart.
But this...!
There was something fundamentally different between the passionate, skin-to-skin intimacy with Takuma and being violated by Ryosuke.
My childhood friend Ryosuke couldn't control his lust, relentlessly thrusting his desires onto me. I was the same, and I thought that was fine. That was how two people were supposed to connect.
"Did your brother's dick used to go here? How did it feel?"
Ryosuke's voice boomed through my foggy mind. Those unnervingly beautiful eyes stared at me with accusatory intensity.
This feels even better now.
Something I could never say aloud.
After overcoming the pain of my first experience, I had come to enjoy having Takuma inside me. I even felt a sense of superiority, thinking I'd finally understood the pleasure of sex.
But now, with just the touch of his hands through my underwear, a terrifying wave of pleasure surged through me. I couldn't even push Ryosuke away anymore. It was all I could do to grip the sheets, barely holding on, afraid my body might fly apart.
"May I touch you directly?"
I couldn't refuse. With the slightest shake of my head, tears that had been building up spilled from the corners of my eyes, their scalding heat soaking Manaka's hair.
"Ugh, Ahh...!"
His fingers parted the slick folds of my intimate flesh.
His fingers were as delicate as they looked, almost frustratingly gentle. Instead of thrusting roughly in and out, they slid into Manaka's folds with a softness that carried an unmistakable resolve.
"Ah... Ah... AHHH!"
Prompted by Ryosuke's fingers, her body overflowed with shameful fluids, soaking her skirt and the sheets.
"Sis, your legs are spread."
Ryosuke's mocking voice pointed it out, but she couldn't control her lower body anymore. Her thighs were parted, allowing his invasion, and when his finger tapped the underside of her abdomen...
"Ah... N-no...!"
Her hips bucked in rhythm with his finger. Even her pathetic state was being scrutinized in detail—every moment he watched, he saw deeper into her.
"Stop! Stop...! I don't know this! I've never felt this before...!"
A soft part of me, unknown even to myself, had been discovered and was being relentlessly tormented. My hips bucked rhythmically, almost as if begging him for more. My body craved his touch, hungered for the shameless pleasure he could teach me, and my sex betrayed me, writhing in helpless submission.
"Wait, wait—ah! Ah!"
My lower abdomen spasmed in quick, violent contractions. Light orgasms washed over me in waves. Shame, humiliation, and an unfamiliar ecstasy I'd never known before made my tears flow uncontrollably.
But just as my consciousness began to drift, something snapped me back to reality.
"Haa, haa... Ryosuke? That's...?"
He paused his ministrations and pulled out his own erection.
I'm transfixed by its erect state—the male organ poised to violate me. It looks far more raw and primal than my lover's. My fingers alone have taught me so much pleasure, but what would happen if something like that were to pierce me?
"No! No...!"
*****
The lewd scent of Manaka fills Ryosuke's nostrils as he looks down at her.
Contrary to her expression of rejection, her vagina glistens with her own slick arousal. Ryosuke presses his glans against her entrance.
Squelch. The folds of her flesh cling to him.
"This seems like it would go in easily, doesn't it?"
It's strange. Just moments ago, her folds were tightly closed, and I never would have believed my erect penis could fit through such a small hole. But now, the moment we make contact, it feels as if she's actively drawing me in.
"I-if you stop now, I'll forgive you..."
"Hm?"
"If you stop now, we'll pretend this never happened, okay? Ryosuke?"
Manaka's face was flushed, her voice urgent.
"You do it with Nii-san, but not with me?"
"Takuma... Aaaaah!"
Thud. The rigid shaft sank deep into her folds. Manaka, who had likely been thinking of her lover moments before, now panted with an indescribable expression.
This... This is intense.
His body was being swallowed by hers. Inside, it was tight. The glans stretched the vaginal walls as he managed to push his penis halfway in.
The sensation of connecting with another person.
The feeling of having sex with his older sister-in-law.
Above all—
"Ah?! Uuuuugh—! You're... you're coming in—!"
Her face twisted with despair, humiliation, and—most of all—uncontainable arousal, stirring a violent lust in Ryosuke. Tears spilled from her squeezed-shut eyes, and saliva dripped from the corners of her clenched mouth.
"Fugh... Uuuugh—"
Manaka desperately stretched out both arms, trying to push my hips away, but there wasn't much force behind her movements. I easily seized her wrists and pulled her closer instead.
"Ah... you're going all the way in."
The slow penetration. Sweat clung to my entire body, but it wasn't unpleasant at all. Covered in sweat, we sank deeper into this forbidden act together.
"Ryo... suke... Aahh!"
When I reached her deepest recess, an indescribable pleasure shot through me, making me shudder. Is this what sex feels like?
Connecting with someone else... Even though I'd been curious before, I'd never really expected it to happen.
Strangers weren't ones to bring me happiness, and I never thought I'd inspire such feelings in anyone. No matter how much I understood what they were thinking, it was all just the result of observation and analysis—my heart had never been moved by such things.
"Nee-san..."
Overcome with emotion, I leaned over Manaka, pressing my lips to hers in a desperate kiss, trying to share this overwhelming feeling.
"Ah! No, not now—mmph, hup, mmm...! Mmm, mmm..."
Manaka protested as fiercely as she had when I first entered her, but as I continued to kiss her, I could feel her tense lower body gradually relax. When I began to move my hips, sliding my penis in and out,
"Ah! Mmm! Mmm—mmf, mmm...!"
Her protests turned into soft, sticky moans. Her body secreted copious amounts of lubrication, her inner flesh melting. The initial pain of penetration had almost vanished; with each thrust of my hips, waves of blissful pleasure erupted from our joined flesh.
"...Nee-san, do you feel..."
I lowered my voice to its most tender register, whispering into her ear as I held her close.
"...like you're having sex with your brother?"
"N-no! Ah! Ahh... Wait, wait...!"
Even as I whispered, I gradually increased the speed of my thrusts. The sound of flesh against flesh seemed almost detached, like it was happening to someone else. Yet the pleasure intensified, becoming terrifyingly overwhelming.
"Alright. Let's make love like we're lovers. I'll do my best for you, Nee-san. Doesn't this feel good?"
"It... it feels so good... Ahh, no, wait, stop, please, please stop— It's too much, it's scary—"
In that moment, I shared Manaka's sensations. This was terrifying. I'd never known such exquisite pleasure existed.
Beyond the physical ecstasy, I could literally feel my older sister-in-law—she who had always strived to maintain family dignity—transforming into a woman with each thrust. Her voice grew sweet, her body soft. The sensation of deep, primal connection between male and female, becoming one.
"Nee-san..."
I could tell my voice was excited by this first-time exhilaration. But this wasn't quite the same as possessiveness. This was the thrill of conquest.
"Who feels better, me or Nii-san?"
"Ugh... Nnnngh... I can't say it... Ahh... I can't take it anymore, Ryosuke... Stop, please, please..."
The soft, full body I held had lost all strength to resist. Not only that, but her voice and skin were now so seductive, it was as if they were coated in pheromones. The elasticity of her breasts against my chest. Initially rejecting me, her greedy pussy now clung desperately to my cock, refusing to let go.
Spasms wracked her body intermittently. She must have been reaching climax repeatedly. Each time, her already tight walls would squeeze down ruthlessly, nearly making me spill my semen over and over.
"Hnngh, Ah, Nnngh... Nngh... Nngh... Ah..."
My older sister-in-law's syrupy voice lodged in my brain, giving birth to a new pleasure that flooded every inch of my body, from crown to toe.
I'm about to drown in the allure of this woman's body. Desperately clinging to my rationality, Ryosuke instinctively straightened up, focusing solely on pounding his hips against her.
This wasn't a calculated move, but it proved effective.
When he looked down at Manaka, she was a different woman from moments before.
Released from his embrace, she gazed up at him with desperate longing, no longer able to suppress her moans. She gasped in short pants in rhythm with his thrusts, her breasts too large to be contained, completely lost in pleasure.
"I can't hold on anymore."
The buried penis in her warm depths burned with frenzied urgency. Clenching his jaw and tensing his hips, he couldn't endure this maddening male desire any longer. The urge to climax deep inside her, to claim every inch of her body, surged through him, but...
"I'll pull out properly. You can come now."
This was his habit. He prioritized fulfilling his partner's desires over his own. But as a result, he succeeded in erasing Manaka's last remaining fear—the dread of being ejaculated inside.
Even as she was shaken by the thrusts in the missionary position, Manaka desperately nodded, yes, yes. Having allowed herself to feel relief, she had, in a way, dismantled her last line of defense against pleasure. Now, with just a few well-placed thrusts, she arched her back and trembled.
"Ryosuke! You're driving me crazy! No, no! Ahh!"
Her writhing vaginal walls tightened around the glans, trying to squeeze out every drop of semen.
"You're about to come too, aren't you?"
"I don't know what's happening! This is my first time—ah! Wait, wait! Ugh, no, Ryosuke! Ry—nnngh...!"
"Hnngh, Nee-san, you're squeezing too hard! Do you really want me to come that badly?"
"Aah! Ah, Auuu... Ah, aaaaah...!"
"Ugh—"
Their bodies tightened rhythmically with the contractions of her womb, climbing toward climax together.
Just in time, he pulled his penis out with a slick slurp, and it jerked violently, spraying thick semen across her white belly. It was an orgasm unlike anything he'd ever experienced, as if every last drop of semen had been wrung from his very core—semen that would normally be aimed at Manaka's uterus now cascaded thickly over her pale abdomen.
"Hii! Nngh... Uwaaaaah...!"
Manaka's lower abdomen spasmed violently, as if in agony, perhaps because she had suddenly lost her mate.
"H-ah...! N-no...! Aah... Aaah...!"
Watching his older sister-in-law climax, drenched in his semen, filled Ryosuke with a sense of conquest.
"Ugh... I'm sorry, Takuma... I'm sorry, Ryosuke...! Hnn... H-ah... Haaah..."
Did she call her lover's name in apology out of shame for yielding to her younger brother, or...
Ryosuke narrowed his eyes and looked down at Manaka.
Her naked body, drowning in the afterglow of pleasure amidst the sea of white sheets, and her expression—
...Perfect.
Something inside Ryosuke snapped. It was a cold, metallic sound, like the transparent shackles that had bound her limbs suddenly breaking free.