The first thing Izuku felt was heat. A solid, heavy line of it against his back. The second was the press of something hard and insistent against the cleft of his ass, separated only by thin cotton. His eyes flew open in the gray morning light. The room was silent except for the sound of his own heartbeat in his ears and the slow, even breath against the back of his neck.

“Daddy?” His voice was a sleep-rough whisper.

“Shhh.” A callused hand slid over his hip, palming the softness of his lower belly, pulling him flush against the hardness behind him. Katsuki’s voice was a low, sober rasp, devoid of last night’s drunken slur. “Don’t move. Just… just let me.”

Izuku went rigid, then pliant. His mind screamed, but his body melted. The sheets smelled like them—sweat, salt, the stale ghost of whiskey. Katsuki’s other hand came up, fingers threading into Izuku’s green curls, not yanking, just holding. A possessive anchor.

“I’m sorry,” Katsuki breathed into his hair, the words a harsh confession. “I woke up like this. Fucking aching. Looked at you… and I couldn’t.” His hips rolled forward, the thick length of him grinding against Izuku through their shorts. A soft, broken sound escaped Izuku’s throat. “See? You’re already wet for me. I can feel it.”

“I’m not,” Izuku lied, the protest weak. He was. A hot, slick soak was already spreading, making the cotton cling. Katsuki’s hand left his belly, dipping beneath the waistband of his shorts. His rough fingertips brushed over his smooth skin, then lower, finding slickness.

“Liar.” Katsuki’s voice was dark, but his touch was different. Sober. Deliberate. He didn’t jam his fingers inside. He circled Izuku’s clit slowly, making him jerk. “My good boy’s always lying. Hates his daddy, but his tiny cunny’s always begging.”

Izuku threw his head back against Katsuki’s shoulder, a tear tracking into his hairline. “I don’t… I don’t hate you.”

“Then what?” Katsuki’s fingers pressed deeper, sliding through his folds with a wet, obscene sound. “Tell me what you are.”

“Daddy’s,” Izuku gasped, his hips pushing back against the hard cock still trapped behind fabric. “I’m yours.”

“Mine to do what with?”

Izuku’s breath hitched. The words clawed their way up from a place of terrible, blooming truth. “To fuck. Your… your cunny boy.”

Katsuki growled, the sound vibrating through Izuku’s spine. The hand in his hair tightened. “My smart boy. Always knew what he was.” He shifted, rolling Izuku onto his stomach. The movement was forceful but controlled. He yanked Izuku’s shorts down to his thighs, exposing him. The morning air was cool on his wet skin.

Katsuki knelt between his spread thighs, his own shorts pushed down just enough to free his cock. It was heavy, flushed and leaking against Izuku’s lower back. He leaned over, his chest a hot weight on Izuku’s back, his mouth at his ear. “I tried to stay away this morning. I fucking tried.” He lined himself up, the broad head nudging against Izuku’s entrance. “But you’re my addiction, Izu. My fucking disease.”

He pushed in. Slow. An inexorable, burning stretch that stole the air from Izuku’s lungs. There was no brutal, drunken slam. This was a sober claiming, inch by devastating inch, until he was fully sheathed, hips pressed flush against Izuku’s ass. They both shuddered.

“God,” Katsuki choked out, his forehead dropping between Izuku’s shoulder blades. “So tight. Always so fucking tight for me.” He didn’t move for a long moment, just breathed, buried inside the heat of his son. When he finally pulled back and thrust, it was with a deep, rolling rhythm that punched a ragged moan from Izuku’s throat. The sound was loud in the quiet room. “That’s it. Sing for me, baby boy. Let me hear how much you love it.”

“I’m sorry,” Katsuki rasped again, his hips grinding to a sudden, shuddering halt. He was buried to the hilt, his breath hot and ragged against the shell of Izuku’s ear. “God, I’m so fucking sorry.” His lips moved against the sweat-damp skin of Izuku’s shoulder, the apology a raw, broken thing. “I don’t wanna hurt you.”

Izuku didn’t answer the apology. A soft whimper escaped his lips, a shuddering exhale against the pillow. He’d heard it before. So many times. The words changed nothing. The thick, full stretch of his father inside him remained, a brutal, grounding truth.

Katsuki’s hips began to move again. Agonizingly slow. A deep, dragging pull back, then a push forward that felt even slower, every ridge and vein of his cock mapped against Izuku’s tight, clenching walls. “Still so fucking tight,” Katsuki groaned into his skin, his voice thick with a wonder that sounded like pain. “After all these years… my baby still fits me like a glove.”

“Daddy,” Izuku breathed, the word a plea for something he couldn’t name—more, less, forever. His fingers twisted in the sheets.

“Feel that?” Katsuki murmured, his pace relentless in its slowness. He rocked forward, a subtle grind that pressed him impossibly deeper. “Feel how deep I am in you? Your cunny’s sucking me right back in. It remembers.”

He slid a hand beneath Izuku, his rough palm finding the soft, small swell of Izuku’s chest, his thumb brushing over a stiff nipple. Izuku arched, a sharp cry tearing from him. “Sensitive,” Katsuki noted, his voice dark with approval. He pinched the bud lightly, rolling it between his fingers as he kept up that torturous, slow thrust. “My good boy’s all worked up. Soaking my cock.”

The wet sound of their joining filled the room, a slick, rhythmic slap that grew louder with each deliberate stroke. Izuku could feel it—the leak of his own arousal, the way his body opened and yielded with every push, betraying him completely. He was pushing back now, meeting each slow drive with a needy tilt of his hips.

“That’s it,” Katsuki growled, his breath hot. “Take it. Take your daddy’s cock. You were made for this. Made for me.” His hand left Izuku’s chest, sliding down the trembling plane of his stomach, over smooth skin, until his fingers found Izuku’s clit.

Izuku jolted, a broken “Ah!” punching out of him. Katsuki circled the swollen nub, the pressure perfect, obscenely skilled. “You gonna come, baby boy?” he whispered, his thrusts never faltering in their slow, deep rhythm. “You gonna cream yourself on my dick like the little slut you are?”

“I’m not—I’m not a slut,” Izuku sobbed, even as his hips stuttered, chasing the friction of Katsuki’s fingers and his cock.

“You are.” Katsuki’s voice lost its softness, turning to gravel. “You’re my slut. My cunny boy. Say it.” He pressed harder on his clit, and Izuku’s vision whited out at the edges.

“Yours!” Izuku screamed, the tension coiling in his gut snapping. “Daddy, I’m yours, I’m your slut—” His orgasm ripped through him, violent and silencing. His back arched off the bed, his channel clamping down in frantic, fluttering pulses around the cock still moving inside him, milking it, drawing a ragged groan from Katsuki’s throat.

Katsuki didn’t stop. He fucked him through it, through the oversensitive tremors, his pace turning sharper, harder, chasing his own end. “Look at me,” he commanded, his voice strained. He hooked a hand under Izuku’s jaw, pulling his head back and to the side until their eyes met—Izuku’s hazy and wet, Katsuki’s crimson and blazing. “Watch me ruin you.”

The command shattered the slow, claiming rhythm. Katsuki’s hips snapped forward, a brutal, driving piston that punched the air from Izuku’s lungs. “Fuck!” The word was torn from him, a raw gasp as the deep, rolling possession became a punishing assault. Katsuki’s hands gripped his hips, fingers digging into the flesh of his thighs, holding him open and still for the savage thrusts. The wet slap of skin grew frantic, obscene, filling the room.

“You take it,” Katsuki grunted, his voice stripped of anything but need. “Take your daddy’s cock, you tight little bitch.” He was chasing his end now, his control unraveling into pure, brutal instinct. Each drive buried him to the hilt, the heavy slap of his balls against Izuku’s skin a rhythmic counterpoint. Izuku could only sob, his oversensitive body alight with a painful, overwhelming pleasure, his own cries choked by the pillow.

Katsuki’s rhythm grew ragged, his breath coming in harsh, open-mouthed pants against Izuku’s sweat-slicked back. “Gonna fill you,” he snarled. “Gonna breed my cunny boy so deep—” But with a final, gut-deep groan, he wrenched himself out. The sudden emptiness was a shock, a cold ache. Before Izuku could process it, he was being flipped onto his back, the world a dizzying blur.

Katsuki loomed over him, his crimson eyes wild, his cock jutting thick and flushed in his fist. He grabbed the hem of Izuku’s thin sleep shirt and ripped. The sound of tearing cotton was sharp, final. Izuku’s small, freckled chest was exposed, his nipples peaked and puffy in the cool air. Katsuki’s gaze devoured him.

“Look at you,” he breathed, his fist beginning to stroke his length in a tight, furious rhythm. Pre-cum beaded and dripped onto Izuku’s sternum, a hot brand. “My perfect boy. My ruined, perfect boy.”

Izuku stared up, transfixed, his green eyes wide. He saw the strain in Katsuki’s jaw, the desperate focus. “Daddy—”

“Watch,” Katsuki commanded, his voice a broken growl. His strokes sped, his hips jerking into his own grip. “Watch me mark what’s mine.” His release hit him like a seizure. A choked roar ripped from his throat as the first thick stripe of cum landed across Izuku’s cheek, hot and viscous. The second splashed over his lips and chin. The third, and fourth, and more—a relentless, possessive painting—arced across his throat, his collarbones, the small, heaving mounds of his chest.

The heat of it was shocking. The smell, salty and musky and uniquely Katsuki, filled Izuku’s nose. He lay perfectly still, painted white, feeling the wetness begin to slide down his skin in warm trails. Katsuki sagged over him, one hand braced by Izuku’s head, his spent cock still dribbling the last drops onto Izuku’s trembling stomach.

For a long moment, Katsuki just looked. His eyes traced the mess he’d made, the proof of his ownership cooling on his son’s skin. The blaze in his gaze softened into something haunted, satiated and sickened all at once. He lifted a trembling hand and brushed his thumb through the mess on Izuku’s cheekbone.

“Izu,” he whispered, the name a wrecked thing.

Izuku’s tongue darted out, a reflexive, shameful movement, catching the bitter-salt taste from his own lip. He didn’t look away from his father’s face. “You said you were sorry,” he murmured, his voice small.

Katsuki’s expression tightened. He leaned down, closing the space between them, and licked a slow, deliberate stripe up Izuku’s cheek, cleaning his own release. “I am,” he said against his skin, the words muffled. “I am so fucking sorry.” He pulled back just enough to meet Izuku’s eyes. “But I’d do it again. Right now. I look at you like this… and I want to do it all over again.”

He lowered his head, his forehead coming to rest against Izuku’s. Their breath mingled. The room smelled of sex and shame and them. Izuku’s clean, freckled skin was sticky and defiled beneath him, and Katsuki held him there, in the ruin, as if it were a sacred altar.

Izuku whimpered, the sound thin and ragged. “No, Daddy. Please, no more.” His hips, still tilting up in tiny, involuntary arcs, betrayed the words.

Katsuki went still above him. He let out a long, shaky breath that stirred Izuku’s sweaty hair. “Fuck.” He pushed himself up, his weight leaving Izuku’s body. The sudden absence of heat was a physical blow. “Get up. Get ready for school.”

“But—”

Katsuki’s hand shot out, not to caress, but to flick sharply at one of Izuku’s swollen, puffy nipples. The sting was bright and shocking. Izuku yelped, his back arching off the bed.

“No buts.” Katsuki swung his legs off the bed, his back to Izuku. His shoulders were tight. “You’re gonna be late. Move your ass.” He stood, pulling his shorts up over his hips. He didn’t look back as he walked to the door. “Make sure you scrub that shit off. I don’t wanna smell me on you all day.” The door clicked shut behind him.

Izuku lay in the wrecked sheets, sticky and cooling. He stared at the ceiling, his chest heaving. The place between his legs throbbed, a hollow, aching pulse. He brought a trembling hand to his nipple, touching the spot Katsuki had struck. It was oversensitive, the pain already fading into a tender heat. A fresh wave of wetness seeped from him, soaking the sheets beneath his thighs. He bit his lip hard to stop the frustrated sob.

The room was silent now, just his own hitched breathing and the distant sound of the shower starting down the hall. The smell of sex was everywhere, thick and undeniable. Izuku pushed himself up, his body sore in a dozen new places. He looked down at himself. The evidence of his father was painted across his skin in drying, pearlescent streaks. He brought his fingers to his chin, gathering a dab, and stared at it.

“Stupid,” he whispered to the empty room. His voice was hoarse from screaming. He swung his legs over the side of the bed, his feet hitting the cold floor. He felt raw, split open. He shuffled to his dresser, catching his reflection in the mirror above it.

He looked ruined. His green hair was matted, his eyes wide and glassy. Freckles stood out starkly on his flushed cheeks, beneath the splatter drying on his skin. He traced a line of it from his collarbone down to the small swell of his chest. A shiver ran through him. He wanted to hate it. He wanted to scrub until his skin was raw.

Instead, he leaned closer to the mirror, his breath fogging the glass. He opened his mouth, just a little, and let his tongue touch the bitter salt on his lip. He closed his eyes, a soft, broken sound escaping him. Down the hall, the shower shut off. The reality of the day—school, notebooks, normalcy—crashed into the haze.

He grabbed clean clothes with clumsy hands, his movements frantic. He had to wash it off. Katsuki said to. But as he hurried toward his own bathroom, the empty, aching throb between his legs followed him, a constant, shameful reminder. He’d said no. He’d begged him to stop.

And all he could think about was the weight of him leaving the bed, and the terrifying, yawning need for it to happen again.