Katsuki's office smelled of leather and power. He sat back in his chair, pants open, his cock heavy and ready against his stomach. Izuku knelt on the plush rug, the position a familiar humiliation, but his father’s gaze held a new intensity—he was being seen, assessed as himself.

“Open,” Katsuki said, his voice a low gravel.

Izuku leaned forward, his lips parting. The thick head pressed against his mouth, already beading with salt. He took it in, the familiar weight and heat, the musky scent of him that was home.

Katsuki’s hand came to rest on his head, not pushing. Just holding. His thumb stroked Izuku’s temple. “Remember the first time I put you here?”

Izuku made a soft sound around him, his eyes fluttering closed. He remembered. The terror. The gagging.

“You cried,” Katsuki murmured, watching him. His fingers traced the shell of Izuku’s ear. “Snot and tears everywhere. Couldn’t take half of it.”

Izuku sucked gently, his tongue working the sensitive slit. He remembered that, too. The shame of failing.

“Took months,” Katsuki said, his voice distant, almost clinical. “Training that gag reflex out. Teaching you to breathe through your nose. Making you taste yourself on me afterward.”

He guided Izuku’s head down, a slow, firm pressure. Izuku relaxed his throat, letting the thick length slide deeper, the stretch a dull, full ache. He focused on the rhythm of his father’s breathing above him.

“You’re good at it now,” Katsuki said, the words rough. “My perfect little cocksleeve. Made you that way.”

Izuku moaned, the vibration earning him a sharp intake of breath. He pulled back, lips slick, and looked up. Katsuki’s crimson eyes were dark, fixed on him with a sober, brutal pride.

“Do you remember why I started?” Katsuki asked, his thumb brushing Izuku’s swollen lower lip.

Izuku shook his head, nuzzling into the touch.

“Because you looked at me,” Katsuki growled. “After. All tear-streaked and used. And you didn’t look at me like I was a monster. You looked at me like I was the only thing left in your world.” He cupped Izuku’s cheek. “That’s when I knew you were mine. Not hers. Mine.”

Izuku took him deeper, his throat working open around the thick intrusion, swallowing around the head until his nose pressed into the coarse hair at the base. He breathed in, the scent of musk and whiskey filling him, and moaned.

“That’s it,” Katsuki growled, his hand fisting in green curls. “Take your daddy’s whole cock. Show me you remember your training.”

Izuku pulled back, lips stretched and wet, gasping for air. “I remember,” he whispered, his voice ragged. He licked a broad stripe up the veined underside. “I remember everything.”

“Do you?” Katsuki’s thumb brushed over Izuku’s fluttering eyelid. “Tell me what you remember.”

“I was scared,” Izuku whispered, his breath hot against the wet crown. He laved his tongue around the thick ridge, tasting salt and skin. “The taste… I thought it was gross. Bitter. Like metal and sweat.”

Katsuki’s hand tightened in his hair, a silent command to continue. His cock twitched against Izuku’s lips.

“I couldn’t take an inch,” Izuku murmured, nuzzling the heavy, full balls that rested against the leather chair. He smelled the musk there, deep and animal. “I gagged. I choked. You had to hold my head still.”

“You cried,” Katsuki grunted, his thumb stroking Izuku’s cheekbone.

“I cried,” Izuku agreed. He opened his mouth and took one heavy testicle inside, sucking gently, feeling the weight on his tongue. He released it with a wet pop. “But then… you came. The first time you finished in my mouth. Down my throat.”

He looked up, his green eyes wide and shining in the lamplight. “I watched your face. I felt you… lose control. And I wanted to make you feel that good again. I wanted to be the reason.”

Katsuki’s breath hitched. “What did you do, baby boy?”

“I practiced.” Izuku’s voice was a hushed, shameful confession. He lapped at the base of Katsuki’s shaft, tracing a thick vein. “With a banana. In my room, after school. I’d try to take it all, to breathe through my nose, to not gag. I timed myself.”

A low, rough sound rattled in Katsuki’s chest. “Fuck.”

“The day I finally took you all…” Izuku whispered, pressing his face into the coarse, dark pubic hair, inhaling deeply. “I was so proud. I felt your balls slap my chin. I felt your hair on my nose. I was full of you, and you… you groaned.” He kissed the skin just above the root, a tender, intimate press of his lips. “I loved it.”

“Show me,” Katsuki commanded, his voice strained. “Show me how proud you were.”

Izuku didn’t hesitate. He opened his mouth wide, letting saliva drip onto the head, and took Katsuki in one slow, deep swallow. His throat opened, a trained, willing relaxation, and he sank down until his nose was buried, until he felt the familiar, satisfying slap of heavy low-hanging balls against his chin. He held there, his eyes watering, his breath coming in soft puffs through his flared nostrils.

Katsuki watched, his crimson eyes blazing. He saw the stretch of Izuku’s lips, the tears clinging to his lashes, the absolute submission. He felt the tight, wet heat of his son’s throat milking him. “My perfect boy,” he rasped, his hips giving a tiny, involuntary jerk. “My good, devoted little cocksleeve.”

Izuku pulled off, gasping, a string of spit connecting his lips to the glistening head. “I am, Daddy,” he panted, his own small chest heaving. “I’m yours. I always practiced to be yours.”

“Fuck my throat, Daddy,” Izuku whispered, his voice ragged from use. His green eyes were wide, pleading. “Please. Be rough with me. Make me gag.” His fingers curled into the hem of his large, soft sweater. He pulled it down, the fabric dragging over his sensitive nipples before it fell, pooling around his elbows and trapping his arms. His small, pale breasts bounced free, the puffy brown nipples already drawn tight. “Fuck my mouth until I drool all over my own tits.”

Katsuki’s crimson eyes darkened, his gaze dropping to the exposed skin. A low groan rumbled in his chest. “Greedy little slut.”

He stood, his shadow swallowing Izuku on the rug. He took his own thick, weeping cock in one hand, the other sinking into Izuku’s green curls. “Open.”

Izuku obeyed instantly, his jaw going slack, his tongue lolling out. He looked up, his expression one of raw, waiting devotion.

Katsuki guided himself to that wet opening. He didn’t ease in. He pushed forward, a hard, brutal shove that buried half his length in one stroke. Izuku’s eyes flew wide, a wet, choked gurgle escaping his stretched lips as his throat was forcibly packed.

“That’s it,” Katsuki growled, his hips pulling back only to piston forward again, deeper. The head bumped the back of Izuku’s throat. “Take it. Just a warm, wet hole for your daddy.”

He set a punishing rhythm, holding Izuku’s head still as he fucked into the tight, clenching heat. The wet, obscene sounds of saliva and flesh filled the office. Izuku gagged, tears springing to his eyes, drool dripping from his chin onto his heaving chest.

“Look at you,” Katsuki snarled, his own breath coming in sharp grunts. “A perfect fucking fleshlight. My personal cocksleeve.” He angled deeper, grinding against the resisting ring of muscle within that tight throat. Izuku’s nose pressed into his lower belly with every thrust. “You love this, don’t you? Love having your throat ruined.”

Izuku couldn’t speak, couldn’t nod. He just moaned, a broken, continuous sound of protest and pleasure that vibrated around Katsuki’s shaft. His spit was everywhere, slicking his chin, his neck, dripping in thin strands onto his pert nipples.

Katsuki slowed, not out of mercy, but to watch. He pulled almost all the way out, letting Izuku gasp in a ragged, wheezing breath. “Tell me why you pulled the sweater down, baby boy.”

“Wanted… wanted you to see,” Izuku croaked, his throat raw. He licked his swollen lips. “Wanted to be messy for you. Wanted to be your toy.”

“You are.” Katsuki thrust back in, deep and slow, making Izuku’s eyes roll back. “My favorite toy. My cunny boy with the pretty little tits.” He used his grip to tilt Izuku’s head back further, exposing the fragile line of his throat. “I should fuck you here until you can’t speak for a week. Until all you taste is me.”

“Yes,” Izuku begged, the word a wet bubble around the intrusion. “Do it, Daddy. Ruin me.”

Katsuki lost the last shred of control. He fucked into that willing mouth with abandon, each thrust a brutal claim. Izuku choked and sputtered, his body shaking, his own tiny clit straining against his pants. He was drowning in it, in the smell of him, the taste, the overwhelming fullness. He was nothing but a vessel, and that was all he wanted to be.

Katsuki’s movements grew jerky, his rhythm faltering. “Gonna fill this greedy throat,” he warned, his voice thick. “Swallow it, boy. Every drop.”

He shoved in one last, devastating time, hilting himself, and held. Izuku felt the hot, familiar pulse against the back of his tongue, the salty flood filling his mouth. He swallowed convulsively, his throat working around the spurting head, drinking him down as tears traced clean lines through the mess on his cheeks.

When Katsuki finally pulled out, Izuku was coughing, strings of spit and come still connecting his lips to his father’s softening cock. He panted, his whole body trembling, his chest slick and shining.

Katsuki looked down at him, his own breathing heavy. He traced a calloused thumb through the mess on Izuku’s collarbone. “My good boy,” he murmured, the growl gone, replaced by something terrifyingly close to tenderness. “My perfect little fleshlight.”

Izuku nuzzled his cheek against the calloused thumb tracing his collarbone. “I love you, Daddy,” he whispered, the words raw and sticky in his wrecked throat.

Katsuki went very still. The tender pride on his face hardened, his crimson eyes searching Izuku’s. “Don’t say that,” he rumbled, but his hand didn’t pull away.

“Why?” Izuku breathed. He turned his head, pressing a kiss to Katsuki’s palm. “It’s true. I love you. I loved you when you trained me. I love you when you ruin me.”

“You love what I do to you,” Katsuki corrected, his voice low. He withdrew his hand to fasten his pants, the gesture abrupt. “It’s not the same thing.”

“It is.” Izuku pushed himself up on trembling arms, his sweater still tangled around his elbows, his small breasts exposed.

Izuku caught Katsuki’s retreating hand and pressed it against his own slick, spit-smeared chest. “Play with them, Daddy,” he whispered, guiding the rough palm over one small, pert breast. “Play with my tits until I cream my panties.”

Katsuki’s fingers twitched against the soft flesh. He didn’t pull away. His thumb brushed a puffy, brown nipple, already tight from the cold air and the earlier abuse. “Disgusting,” he rumbled, but he circled the peak, feeling it harden further under his calloused touch.

“I love you,” Izuku breathed, arching into the contact. “I love you so much it hurts right here.” He tapped his own chest, over his heart. “I’m yours. Your cunny boy. Your sex doll. Nothing else.”

“You’re a desperate slut is what you are,” Katsuki said, but his other hand came up to pinch the opposite nipple, rolling it harshly between his fingers.

Izuku cried out, a sharp, sweet sound. “Yes! Just a slut. Your slut.” He ground his hips against nothing, the damp fabric of his pants rubbing his swollen clit. “I practiced for you. I trained for you. My whole body is just… just for you to use.”

Katsuki leaned down, his breath hot against Izuku’s ear. “You think this proves something?” He squeezed both breasts together, his big hands making the small mounds look even more delicate. “This just proves you’re a good little hole. Responsive. Needy.”

“I am,” Izuku sobbed, his eyes fluttering shut as Katsuki’s thumbs scraped over his nipples. A fresh wave of wetness soaked his underwear, the scent of his own arousal mingling with the musk of Katsuki’s spend in the air. “I’m your good boy. Your devoted boy. Please, Daddy… don’t stop.”

Katsuki watched the tears leak from beneath Izuku’s lashes. He watched the way his son’s mouth stayed open, panting, begging. He lowered his head and took one tightened peak into his mouth, sucking hard.

Izuku screamed, his back bowing. The sensation was electric, a sharp pull that shot straight to his dripping cunt. He tangled his hands in Katsuki’s spiky hair, holding him there. “More, more, more…”

Katsuki switched to the other, biting gently, then soothing with his tongue. He spoke against the damp skin, his voice a vibrating growl. “You cream those panties yet, baby boy?”

“Almost,” Izuku whimpered, his hips rocking in frantic, tiny circles. “I’m so close, Daddy. Just from your mouth on my tits. I’m so pathetic for you.”

“You are.” Katsuki pulled back, his lips glistening. He looked down at Izuku’s ruined sweater, his heaving chest, his utterly wrecked face. For a long second, the only sound was Izuku’s ragged breathing. Then Katsuki’s hand slid down, over the trembling belly, and pressed firmly against the soaked fabric between Izuku’s thighs. “Cream for me.”

The command, the pressure, the sheer possessiveness of it shattered Izuku’s last thread of control. He came with a broken wail, his cunt clenching around nothing, a hot flood of release saturating his underwear and dripping onto the rug beneath him. His body shook violently, overwhelmed.

Katsuki kept his hand pressed there, feeling the pulses through the fabric, until the tremors subsided into weak twitches. He slowly withdrew his hand and held his glistening fingers up to the lamplight. “Look at that,” he muttered, his voice devoid of its earlier cruelty. “Soaked.”

Izuku, spent and boneless, gazed up at him with absolute worship. “All for you,” he slurred, his mind hazy with pleasure and devotion. “Always for you.”

Katsuki stared at his wet fingers, then at Izuku’s blissful, tear-streaked face. The conflict was a physical tension in his jaw. He wiped his hand clean on the hem of Izuku’s sweater. “Get up,” he said, the words rough but lacking their earlier edge. “Let’s go clean up, baby.”