The classroom was empty after hours, but Izuku felt more exposed than ever. Katsuki’s desk was hard against his back, the lesson plan for tomorrow crumpled beneath his trembling thighs. Every filthy detail he whispered into Kacchan’s ear made the teacher’s cock twitch against his hip, a hot, possessive brand.

“He came inside me,” Izuku breathed, the words a humid confession against Katsuki’s jaw. “Right there. With her sleeping next to us.”

Katsuki’s hand, splayed on Izuku’s belly, flexed. “Tell me what he said.”

“He… he made me look at her. He said I was a disgrace.” Izuku’s voice hitched, not with shame, but with a dizzying thrill. “He said I was born to be a cunt.”

“Good.” Katsuki’s other hand came up, fingers digging into the soft flesh of Izuku’s tiny tit, pinching the puffy brown nipple until Izuku gasped. “And you came for him.”

“I squirted. All over their sheets.”

A low, approving growl vibrated through Katsuki’s chest. He rocked his hips, the thick ridge of his cock, still confined in his trousers, grinding against Izuku’s damp, shaved pussy through the boy’s thin uniform skirt. The friction was maddening. Izuku could feel his own wetness soaking through the fabric, a slick patch growing hotter under the relentless pressure.

“Again. Two days later. In the living room.” Katsuki’s command was a razor. “Details.”

Izuku’s head fell back against the desk, the chalk dust smell filling his nose. “He bent me over the chair. Made me look at the family photo. He said… he said ‘this is my son’ while he was fucking me.” The admission tore out of him, a forbidden truth that made his cunt clench on nothing, aching. “And I said it back. I said ‘I’m your son’.”

Katsuki’s breath hitched. His crimson eyes burned with a dark, possessive fire. “You’re mine.” He stated it like a law of physics, unchangeable. His hands went to his belt, the click of the buckle obscenely loud in the silent room. “You degrade yourself for them, but you *come* for me. You exist for this.” He shoved his trousers and briefs down just enough to free his cock, massive and uncut, the head already glistening. It slapped heavy against Izuku’s inner thigh.

He didn’t bother with Izuku’s skirt, just yanked the damp fabric of the boy's panties aside. The broad, hot crown of his cock pressed against Izuku’s dripping entrance. Izuku whimpered, his small body arching, his bug-bite tits pebbling tight under his button up.

“Who do you belong to, Izuku?”

“Kacchan,” Izuku sobbed, the secret name a prayer.

Katsuki drove into him in one brutal, claiming thrust. The desk shuddered. Izuku cried out, the stretch a perfect, familiar burn, the fullness so deep it stole his breath. Late afternoon sun cut across them, highlighting the sweat already beading on Katsuki’s forehead, the desperate flutter of Izuku’s freckled thighs around his teacher’s hips.

“Tell me what he tasted like,” Katsuki grunted, his hips pulling back just an inch before slamming home again, the desk leg scraping against the floorboards. The deep, grinding thrust forced the air from Izuku’s lungs.

“S-Salt,” Izuku gasped, his fingers scrambling against the polished wood. “Like skin. Like… me.”

Katsuki’s next thrust was slower, a deliberate, penetrating roll that buried him to the hilt and held there, making Izuku feel every thick, veined inch. “Where did he kiss you?”

“My neck. My shoulders.” Izuku’s head lolled, his vision blurring as the pleasure built, a direct line from his brutally stretched cunt to his throbbing clit. “He bit me. Here.”

He touched his own collarbone, and Katsuki leaned down, his mouth replacing Izuku’s fingers, teeth sinking into the same spot. The sharp pain bloomed into heat, and Izuku cried out, his back arching off the desk, his tiny tits bouncing with the force of Katsuki’s next punishing drive.

“He’s a weak fucking substitute,” Katsuki snarled against his skin, his breath scalding. “A placeholder. You take his cock and you think of mine.”

“I do,” Izuku whimpered, the confession ripped from him. “Every time. I thought of you, Kacchan. I thought of your desk… your hands…”

“Prove it.” Katsuki’s pace became erratic, brutal, his balls slapping against Izuku’s ass with each drive. “What did you imagine? Here. Now.”

Izuku sobbed, the words tumbling out between shattered breaths. “This. You f-fucking me on your desk. Making me say it. Making me yours in your classroom where everyone sees you as a teacher—”

Katsuki’s hand clamped over his mouth, muffling him. The other hand gripped Izuku’s hip hard enough to bruise, holding him still for a deep, circular grind that made Izuku’s eyes roll back. “They see a teacher. You see the man who owns you. You’re the only one who gets the truth. The only one who gets this.”

He removed his hand from Izuku’s mouth, trailing it down the boy’s quivering belly, to his damp bald pussy, until his thumb found Izuku’s swollen, needy clit. The direct pressure was electric, devastating.

“I’m gonna come,” Izuku warned, his voice high and thin. “Kacchan, please—”

“Not yet.” Katsuki’s thumb pressed harder, circling, but his hips slowed to a torturous, shallow pump, just the head of his massive cock stretching Izuku’s entrance with each tiny thrust. “You don’t come until you admit what you are.”

“Yours,” Izuku choked out, his hips trying to chase the deeper penetration, but Katsuki held him pinned.

“What else?”

Izuku’s green eyes, glazed with pleasure, found Katsuki’s burning crimson gaze. The words were a sacred, filthy vow. “Your fuckhole. Your cunt. You trained me for your cock. Only yours.”

“Good boy.”

The praise was all the permission he needed. Katsuki pistoned into him, fast and deep, the slap of skin echoing off the chalkboards. Izuku’s world dissolved into sensation—the burn of the stretch, the searing friction, the relentless rub on his clit. His little tits bounced with every impact, his nipples hard peaks against his rumpled shirt. He babbled, a stream of “Kacchan, Kacchan, Kacchan,” as the coil in his gut wound tighter, unbearable.

“Now,” Katsuki commanded, his own control fraying, his rhythm breaking.

Izuku shattered. His cunt clenched in a rapid, fluttering rhythm around Katsuki’s driving cock, and he squirted, a hot gush that soaked the skirt bunched around his waist and dripped onto the lesson plans below. The orgasm wrung through him, endless, wracking his small frame with tremors.

Katsuki followed with a guttural groan, slamming home one final time and holding there, his hips stuttering as he emptied himself deep inside. Izuku felt the hot pulse of it, the intimate claim, and a second, weaker wave of pleasure shuddered through his oversensitive body.

Katsuki stayed buried within him, his weight a heavy, comforting anchor. He looked down at Izuku’s wrecked, blissful face, the freckles standing out against his flushed skin.

“The details,” Katsuki said, his voice rough but calm, a teacher delivering the core lesson. “They’re just data. The conclusion is all that matters. You. Are. Mine.” He punctuated each word with a slow, possessive grind, still half-hard inside him. “Everything else is just practice for the real thing.”

Katsuki’s hips began to move again, a slow, deliberate rekindling of the fire. His cock, still slick from his own release and Izuku’s squirt, slid easily inside the boy’s well-used cunt. “You’re not done,” he growled, his voice thick with renewed intent. He set a deep, grinding rhythm that made the heavy teacher’s desk creak in protest, its legs scraping a steady beat against the floorboards.

“Kacchan—” Izuku gasped, his oversensitive body arching into the renewed friction.

“Shut up and listen.” Katsuki’s hands gripped Izuku’s hips, lifting and driving into him with more force, the slap of skin echoing. “I’ve got a new lesson plan. For Friday.”

Izuku’s green eyes, dazed with pleasure, tried to focus on his teacher’s face. The desk rocked with every thrust. “F-Friday?”

“Your mother. She’s getting a spa weekend. My treat.” Katsuki’s lips curled into a sharp, predatory smile. “A two-night stay. She’ll be gone by Friday afternoon.”

He punctuated the plan with a brutal snap of his hips, forcing a choked cry from Izuku. “You and me. We’re going to your house. You’re going to strip the second we’re inside. You’ll be naked. I’ll be in my suit.”

“Why?” Izuku whimpered, his mind struggling to keep up as his body burned.

“Because you’re going to kiss me. You’re going to beg against my mouth while I’m still dressed for work.” Katsuki leaned down, his breath hot on Izuku’s ear. “And then your father will come home.”

The words cut through the haze of pleasure like ice. Izuku’s cunt fluttered tight around Katsuki’s cock. “Daddy…”

“You’re going to look him in the eye.” Katsuki’s pace became punishing, relentless, driving the plan into Izuku with every thrust. “And you’re going to beg him. ‘Please, Daddy. Fuck me with Kacchan.’”

Izuku’s head thrashed against the desk. The image was too vivid, too depraved. A fresh wave of slick heat soaked Katsuki’s cock. “We can’t—”

“We will.” Katsuki’s hand fisted in Izuku’s green curls, forcing his head still. “You’ll take us both. However we want you. You’re my perfect little fuckhole, aren’t you? Trained for my cock. Now you’ll prove it can handle more.”

“Yes,” Izuku sobbed, the resistance melting into a terrifying, eager hunger. The desk groaned beneath them, a frantic soundtrack to the corruption being etched into his soul. “Yes, Kacchan.”

“Good.” Katsuki’s rhythm shifted, becoming faster, more erratic. His control was slipping, the vision of his plan pushing him toward the edge. “You’ll belong to both of us in that house. But you’ll remember who you really come for.”

Izuku could only nod, his words stolen by the sensation of being split open, owned, and plotted for. His small tits bounced with the violent motion, his nipples scraping against his shirt. The coil in his gut wound tight again, fueled by shame and a dark, yawning need.

“Come for me, Izuku,” Katsuki commanded, his voice a ragged growl. “Come thinking about his cock in your ass while I’m in your cunt.”

The filthy permission shattered him. Izuku screamed, his back bowing off the desk as another orgasm ripped through him, a gush of wetness spilling between them. Katsuki followed with a final, deep thrust, burying himself to the hilt as he emptied another hot, claiming pulse inside him.

He collapsed over Izuku, his weight pressing the boy into the hard wood. The only sounds were their ragged breaths and the slow, final creak of the settling desk. Sunlight striped the mess they’d made of the lesson plans.

Katsuki nuzzled into the sweaty crook of Izuku’s neck, his voice a low, satisfied rumble. “Friday. It’s a date.”