The front door clicks shut. The sound is final, like a lock turning. Izuku doesn't move. He stares at the wood grain, listening to the fading sound of Masaru’s car engine. The house is silent. Full. Heavy.

“He’s gone for a whole week.”

Katsuki’s voice is behind him, close. Not a whisper. A statement. A fact that hangs in the entryway air, thick with the leftover scent of Masaru’s cologne.

Izuku swallows. His hands are trembling. He clasps them together. “Yes.”

“Look at me, Mom.”

Izuku turns. Katsuki is right there, his crimson eyes sharp, fixed. He hasn’t moved an inch. He’s still dressed, handsome in a casual sweater and jeans, but Izuku can see the thick outline of his cock against the denim. It’s already hard. Waiting.

“You know what we’re doing,” Katsuki says. It isn’t a question.

“Our room,” Izuku whispers. The words taste like betrayal.

“Your marital bed. Where Dad sleeps. Where he fucks you.” Katsuki takes a step forward. The space between them vanishes. “Where I’m going to breed you.”

A shudder runs through Izuku’s whole body. It’s fear. It’s heat. It’s a terrible, shameful flood between his thighs. “Kacchan…”

“Take off your clothes. Here. Now.”

Izuku’s fingers fumble with the hem of his soft cotton shirt. He pulls it over his head, his green curls mussed. The air in the entryway is cool on his bare skin, on his small, soft tits. He unsnaps his jeans, pushes them and his panties down his thick thighs in one motion, stepping out of the pooled fabric. He stands naked before his son, in the place where he kissed his husband goodbye twenty minutes ago.

Katsuki’s gaze is a physical weight. It travels over Izuku’s freckled skin, his rounded stomach, the silver marks, the curves, tight pussy already glistening. “You’re wet for it,” he says, voice low. “You’re so wet for me to fuck you in Dad’s bed.”

Izuku says nothing. He can’t. The truth is a knot in his throat.

Katsuki closes the last inch. His hand comes up, not to touch, but to hover just above Izuku’s cheek. “Tell me you want it.”

“I…” Izuku’s eyes burn. “I want you to stop hurting people.”

Katsuki’s hand doesn’t move from its hover near Izuku’s face. His eyes narrow, just a fraction. “I haven’t touched anyone else in weeks. Not since you offered. Not since the first time I had your pussy in my mouth.”

Izuku’s breath hitches. The admission hangs between them, a twisted balm on the open wound of his sacrifice.

“You are keeping me well fed, Mommy.” Katsuki’s voice drops, becoming intimate, conspiratorial. His thumb finally makes contact, stroking the wet track of a tear on Izuku’s cheek. “Why would I possibly want anyone else’s bitch cunt when I have yours?”

His other hand moves down, fast and deliberate. His fingers press flat against Izuku’s lower belly, then slide through the slick, curly hair. He doesn’t tease. He pushes two thick fingers into the soaked, clutching heat of Izuku’s pussy.

Izuku cries out, a sharp, broken sound. His knees buckle. Katsuki’s fingers inside him are an anchor, a violation, a relief. They curl, pressing up into a spot that makes white light flash behind Izuku’s eyelids.

“See?” Katsuki breathes, his face inches away. He works his fingers slowly, the wet sound obscene in the silent entryway. “Perfect. Made for me. Always ready. Always wet. My personal cunt.”

Something in Izuku shatters. The last fragile wall of denial crumbles under the physical proof—his own body’s traitorous, dripping welcome. A sob tears from his throat. “Kacchan… please.”

“Please what, Mommy?” Katsuki croons, fucking him slowly with his fingers. “Use your words.”

“Fuck me.” The words are a ragged whisper, then a desperate moan as Katsuki’s thumb finds his clit. “Oh, god—fuck my pussy. Please. I need it. I need you to—”

“To what?”

“Breed me!” Izuku shouts it, the plea echoing off the walls Masaru painted. His hands clutch at Katsuki’s sweater. “Put it in me. Fill me up. Put your baby in me, put your sibling in my womb, please, Kacchan, I can’t—I need your cock, I need it now—”

Katsuki pulls his fingers out with a slick pop. He brings them to Izuku’s mouth, smearing the glistening wetness across his mother’s trembling lips. “That's a good mommy.”

Katsuki’s eyes darken, the crimson going molten. He doesn’t reply with words. He simply bends, hooks his arms under Izuku’s bare thighs, and lifts him as if he weighs nothing.

Izuku gasps, his legs instinctively wrapping around his son’s waist. His arms circle Katsuki’s neck, holding on. The solid, muscular heat of him is everywhere. “Kacchan—”

“Shut up,” Katsuki murmurs, but there’s a wild, eager grin on his face. He turns and starts walking toward the stairs, carrying his naked mother easily. “Just hold on, Mommy.”

Izuku does. He buries his face in the curve of Katsuki’s neck, breathing in the sharp, clean scent of him, so different from Masaru’s soft cologne. Then, driven by a need that feels like drowning, he finds Katsuki’s mouth with his own.

The kiss is messy, desperate. Izuku licks into his son’s mouth, tasting pure Katsuki. He moans, arching against the hard plane of Katsuki’s chest.

Katsuki groans into the kiss, his grip tightening. He takes the stairs two at a time, never breaking the feverish seal of their mouths. The house feels like a cocoon, silent except for their ragged breathing and the soft thud of Katsuki’s footsteps on the carpet.

He shoulders open the door to the master bedroom—Izuku and Masaru’s sanctuary. The large bed with its crisp, neutral linens is a stark altar in the afternoon light filtering through the blinds.

Katsuki doesn’t lay Izuku down gently. He falls with him onto the mattress, the impact bouncing them. The kiss finally breaks. They’re both panting, chests heaving.

“Clothes,” Izuku gasps, his hands scrambling at Katsuki’s sweater. “Off. Now.”

Katsuki laughs, a low, breathless sound of pure hunger. He yanks the sweater over his head, revealing the sculpted chest and abdomen Izuku has felt but rarely seen in full light. Izuku’s hands are already at his jeans, fumbling with the button and fly.

“Hurry,” Izuku whines, pushing the denim down Katsuki’s hips. The massive, hard line of his cock springs free, slapping against Izuku’s trembling stomach. It’s hot, heavy, uncut and leaking. Izuku’s mouth waters. “Please, I need it. I need you in me.”

Katsuki kicks his jeans and boxers the rest of the way off. He’s fully naked now, kneeling over Izuku on the bed his father shares with his mother. His cock, thick and girthy and flushed dark, bobs between them. “You see what you do to me?” he grits out. “Look at it. It’s yours. It’s always been for you.”

Izuku’s green eyes are wide, fixated on the sheer size of him. He reaches down, wrapping his own slick fingers around the base. He can’t close his thumb and forefinger. “I know,” he whispers, then his voice cracks into a sob. “I need it, Kacchan. I’m so empty. I need that giant cock fucking me, filling me up. Please, baby boy, don’t make me wait.”

Katsuki’s control snaps. The intention to tease evaporates under the raw plea in his mother’s voice. “You want it that bad, Mommy?” He shifts, using his knees to nudge Izuku’s thighs wider apart. The head of his cock presses against the soaked, swollen entrance of Izuku’s pussy. “You want my sibling in your womb that badly?”

“Yes!” Izuku cries, his hips bucking up, trying to force the tip inside. “Yes, I do! Breed me, Kacchan. Put it in. Put your baby in me. Fuck your perfect pussy, please!”

Katsuki’s breath hitches. He looks down, watching where they are about to join, in his father’s bed. A possessive snarl tears from his throat. He pushes forward.

Katsuki pushes, and the stretch is immediate, brutal, perfect. Izuku’s head falls back against his father’s pillow, a shattered moan tearing from his throat as the thick, fat head of his son’s cock forces his way inside. There’s a burning fullness, a deep, claiming pressure that steals the air from his lungs. Katsuki doesn’t stop. He drives forward in one relentless, smooth stroke, burying himself to the hilt until his hips are flush against Izuku’s ass, until Izuku can feel him nudging deep, deep inside, a pressure against his womb.

“Fuck,” Katsuki grunts, his voice ragged. He pauses, buried completely, his body trembling with the effort of holding still. His crimson eyes are wide, locked on where they’re joined. “Oh, fuck, Mommy. You’re so tight. You’re swallowing me.”

Izuku’s hands scramble against the neutral linen duvet, gripping fistfuls. His eyes are screwed shut, tears leaking from the corners. The invasion is total. It’s a violation of every vow in this room, and his body sings for it. “Kacchan,” he whimpers.

“Look at me.” Katsuki’s command is guttural.

Izuku forces his eyes open. His son’s face is above him, flushed, handsome, utterly possessed. Katsuki begins to move.

It’s not a rhythm. It’s a punishment. A claiming. He pulls back almost all the way, the drag making Izuku cry out, then slams home again, the impact jolting Izuku up the bed. The wet, slapping sound of skin on skin fills the quiet bedroom. Each thrust is deliberate, brutal, aimed deep. Katsuki’s hands grip Izuku’s hips hard enough to bruise, holding him in place to take every inch.

“Yours is so much bigger,” Izuku gasps, the words tumbling out unbidden, punched from him with a particularly deep stroke. His eyes are glazed, fixed on Katsuki’s face. “God, it’s so much bigger than your father’s.”

Katsuki’s hips stutter. A feral grin splits his face. “Yeah?”

“Yes,” Izuku moans, his back arching. He’s babbling now, the truth spilling out like a confession. “Masaru—he never fills me up like this. He never reaches… there. You’re in so deep, baby boy. You’re hitting places he’s never touched.”

“Tell me more,” Katsuki snarls, his pace becoming erratic, possessive. He leans down, his breath hot against Izuku’s ear. “Tell me how much better your son’s cock is.”

“It’s thicker,” Izuku sobs, his hands coming up to claw at Katsuki’s sweat-slick back. “It’s so thick I can feel it stretching me open for days after. And it’s longer. You bottom out inside me. You own places in my body he doesn’t even know exist.”

Katsuki moans, a raw, unguarded sound. He fucks into him harder, the bedframe knocking a steady rhythm against the wall. “What else, Mommy?”

“The way you feel,” Izuku pants, his words dissolving into a scream as Katsuki angles a thrust that lights up his nerves. “He’s soft. You’re… you’re hard everywhere. All the time. You’re always ready for me. Your cock is always so hard and hot and hungry for my pussy. His just… gets the job done. Yours… yours ruins me.”

“That’s right,” Katsuki breathes, his composure fraying. His thrusts are losing their brutal control, becoming frantic, desperate. “I ruin you. This perfect pussy is mine. I’m the only one who knows how to fuck it right. The only one who knows how to make my mommy scream.”

Izuku nods wildly, his green curls stuck to his damp forehead. “Yes. Only you. You fuck me better than my husband. You fuck your mommy better than your daddy ever could.”

The admission, spoken aloud in the bed he shares with Masaru, seems to unleash something final in Katsuki. A guttural sound rips from his chest. He crushes his mouth to Izuku’s, swallowing his mother’s cries as his hips piston wildly, erratically, chasing his end. The wet, messy sounds of their joining are the only music in the room.

Katsuki’s frantic pace suddenly hitches. A raw, wounded sound escapes his throat. He buries his face against Izuku’s neck, his hips stilling deep inside, his entire body trembling with the effort of holding back.

“No,” he grunts, the word muffled against damp skin. “Not yet.”

“Kacchan?” Izuku whispers, his hands coming up to cradle the back of his son’s head.

Katsuki pulls back, his crimson eyes blazing with a desperation Izuku has never seen. “I’m not coming yet. I can’t. Not yet.”

“Why?”

“Because this,” Katsuki says, his voice cracking. He shifts his hips slightly, making Izuku gasp as he’s reminded of the full, thick presence inside him. “This pussy. It’s all I ever wanted. Do you understand? It’s the only thing I ever fucking wanted.”

Izuku stares up at him, his breath caught.

“Every other one was a placeholder,” Katsuki continues, the words pouring out in a harsh, confessional rush. His composure is gone, stripped bare. “Every boy pussy, every fucking ‘available’ cunt I took… it was just because I couldn’t have this one. I was so fucking frustrated. I’d see you in the kitchen, bending over, or laughing, and I’d get so hard it hurt. And I’d have to go out and find someone to ruin just to stop from going insane.”

He leans down, his forehead pressing against Izuku’s. “My first boner was for you. I was thirteen. I woke up aching, and all I could think about was shoving it into my mommy’s perfect, fat pussy. I’ve needed it ever since. I need it.”

Izuku’s eyes well with tears. This isn’t the cold predator from the tapes. This is his little boy, desperate and hungry, confessing a sickness that has always had his name on it.

“Please,” Katsuki whispers, and the word is so foreign on his tongue it sounds broken. “Please, Mommy, don’t ever take it away from me. Let me have this. Let me fuck this pussy forever. I’ll die without it. I will.”

The raw, vulnerable begging unravels something deep in Izuku’s chest. The sacrifice curdles into something else, something tender and horrifying and possessive. He cups Katsuki’s face, his thumbs stroking the sharp cheekbones.

“Oh, Kacchan,” Izuku breathes, his voice thick. “My baby boy.”

“Promise me,” Katsuki insists, his hips giving a shallow, pleading thrust. “Promise it’s mine.”

“It’s yours,” Izuku says, the vow leaving his lips like a sacrament. “It’s always been yours. You can have it whenever you want. Anywhere in this house. Any time of day. In the kitchen, the living room, the goddamn backyard.”

Katsuki’s eyes widen, a desperate hope blazing in them.

“Anywhere in public,” Izuku continues, pulling his face closer. “In a store. In a park. Even… even in front of your father, if that’s what you need. This is your cunt now, Kacchan. Your free-use pussy. To do with whatever you want. However you want. Forever.”

A broken, relieved sob escapes Katsuki. He crashes his mouth down onto Izuku’s.

The kiss is a vow. It’s messy, all tongue and teeth and shared breath, wet with tears and sweat. Izuku pours everything into it—a mother’s forgiveness, a lover’s surrender, the terrifying commitment to his own damnation. He kisses back with equal fervor, his hands tangling in spiky blond hair, holding him close.

Katsuki begins to move again, his thrusts returning not with brutal punishment, but with a deep, reverent desperation. Each push is a prayer, each drag a confirmation. “Mommy,” he chants against Izuku’s lips. “My Mommy. My pussy. Mine.”

The coil of pleasure that had ebbed reforms, tighter and hotter than before. It builds from the deepest part of Izuku, from where Katsuki’s cock is spearing him, claiming the promise he just made. “Yes,” Izuku gasps into the kiss. “Yours. Come on, baby. Breed it. Fill your mommy up. Make it yours forever.”

The permission is the final key. Katsuki’s control shatters completely. His thrusts become wild, unfocused, pure instinct. He moans, a long, guttural sound of release, as his hips slam home and stay there.

Izuku feels the hot, sudden pulse deep inside him. The flood of Katsuki’s climax triggers his own. His back arches off the bed, a silent scream on his lips as the pleasure detonates. It rips through him, wave after wave, and he feels the gush of his own release, squirting around the thick cock buried in him, soaking the sheets beneath them.

They climax together, locked in the kiss, in the bed, in the vow. Katsuki pumps his seed into his mother’s womb in deep, rhythmic pulses, claiming the space his father never could. Izuku milks him through it, his inner walls clenching and fluttering, accepting every drop.

Slowly, the world filters back in. The tick of the wall clock. The smell of sex and cedar. The slick, joined heat of their bodies.

Katsuki collapses on top of him, his weight a solid, anchoring warmth. He nuzzles into the crook of Izuku’s neck, his breathing ragged. “Mommy,” he whispers, the word full of awe.

Izuku stares at the ceiling, his hands stroking through damp blond hair. His body is thoroughly used, utterly claimed. His husband’s seed has been washed away, replaced by his son’s. The proof is leaking out of him, onto Masaru’s side of the bed.

He feels a strange, terrible peace.

Izuku tilts his chin up and finds Katsuki’s mouth again. The kiss is softer this time, languid and deep. It tastes like salt and surrender.

“Again,” Izuku murmurs against his lips, his hands sliding down to grip Katsuki’s hips. “Fuck me again, Kacchan. Slower.”

Katsuki makes a low, affirmative sound. He shifts, still buried inside, and begins to move. The pace is a deliberate, rolling grind. There’s no violence left in it, just a desperate, aching connection.

“Look at me,” Izuku whispers.

Crimson eyes lock with green. The predatory chill is gone, replaced by something raw and open. Katsuki’s breath hitches. “Mommy.”

“I love you,” Izuku says, the words leaving him like a breath he’s been holding for twenty-two years. “My perfect, broken boy. I love you so much it’s eating me alive.”

Katsuki’s rhythm stutters. A tear escapes, tracing a path through the sweat on his temple. He doesn’t wipe it away. “You shouldn’t.”

“I know.”

“I’m a monster.”

“You’re my monster,” Izuku corrects, his voice thick. He wraps his legs tighter around Katsuki’s waist, pulling him deeper. “And I’m yours. All the way down.”

Katsuki bows his head, his forehead resting against Izuku’s. His thrusts are slow, deep circles that make Izuku’s toes curl. “I love you,” he whispers, the confession ripped from a place he’s never shown anyone. “It’s the only real thing in me. It’s why everything else is so fucking dark.”

Izuku frames his son’s face with trembling hands. “Then let it be light. Here. With me. Just this.”

They move together in the ruined marital bed, a slow, wet rhythm that feels less like fucking and more like a heartbeat. The outside world—the neighbors, the tapes, Masaru—fades into a distant hum. There is only this room, this smell of sex and cedar, this joining.

“You feel so perfect,” Katsuki breathes, his eyes drifting shut. “This pussy… it’s so warm. It’s holding me so tight.”

“It’s yours,” Izuku reminds him, arching into each slow thrust. “It’s always going to be this warm for you. Always this wet.”

Katsuki opens his eyes. The reverence in his gaze is terrifying. “I’m gonna put a baby in it.”

“I know.”

“You want that?”

Izuku doesn’t hesitate. “Yes. I want your baby. I want to be fat with your child. I want to give you a sibling.”

A choked sob escapes Katsuki. He buries his face in Izuku’s neck, his hips never stopping their gentle, insistent rhythm. “Thank you,” he mumbles against freckled skin. “Thank you, Mommy. Thank you.”

They don’t speak for a long while after that. The only sounds are their mingled breaths, the soft slap of skin, the wet slide of Katsuki moving inside him. Izuku drifts on the sensation, a floaty, full-body peace settling over him. This is wrong. This is damning. But in this moment, with his son’s weight pressing him into the mattress, it feels like the only truth he’s ever known.

The climb back to climax is a slow, sweet burn. It builds in Izuku’s belly, a warm pool of pleasure that spreads with every deep, claiming stroke. He can feel Katsuki’s control fraying again, his thrusts becoming less measured, more urgent.

“I’m close,” Katsuki gasps.

“Me too.” Izuku tangles a hand in blond spikes. “Look at me when you come. I want to see it.”

Katsuki obeys, lifting his head. His eyes are glazed, vulnerable. “I love you,” he says again, like a prayer.

“I love you, Kacchan. Now fill me up. Breed your mommy right.”

The command shatters him. Katsuki’s orgasm hits with a low, guttural cry, his body locking as he pumps another hot, claiming load deep into Izuku’s womb. The feeling of being filled a second time, so soon after the first, triggers Izuku’s own release. It’s a softer wave this time, a warm, pulsing spill that leaks out around Katsuki’s still-throbbing cock.

They stay joined, Katsuki’s weight a welcome anchor, as their breathing slowly evens out. The afternoon light has shifted, painting the room in gold.

Katsuki finally shifts, pulling out slowly. He collapses onto his side, facing Izuku, one hand coming to rest possessively on his mother’s sticky stomach. “Mine,” he murmurs, his eyes already heavy.

Izuku turns toward him, curling into his son’s body. He kisses Katsuki’s collarbone. “Yours.”

Within minutes, Katsuki is asleep, his breathing deep and even. Izuku watches him. The fierce lines of his face are soft in repose. He looks young. He looks like his little boy again.

“I love you so much, baby boy,” Izuku whispers into the dark space between them, his lips brushing Katsuki’s sweat-damp skin. The words are a final, soft surrender before his body goes heavy, his breathing deepening into the steady rhythm of sleep against his son’s chest.

Katsuki’s arm tightens around him in sleep, a possessive reflex. They lie tangled in the center of the marital bed, the sheets cool where they aren’t soaked with the proof of what they’ve done.