"You should have known your mouth was going to get you into trouble."

The sound of Iida's voice sends a shiver down Shinsou's spine but, staying in character, he continues to glare resentfully up at him. His knees are protesting the hard floor, aching, and there's a tingle in his toes, but he won't move. If he moves even a little bit, the handcuffs will clink and Iida will know. He flexes his fingers and toes, trying to stave off any numbness, and takes a slow breath through his nose, saliva collecting around the gag.

Between his lips, it feels almost heavy, stretching his mouth wide but filling it with an unrelenting sphere. The straps are soft but unmoving, keeping him at Iida's mercy. Drool collects under his tongue, behind his teeth, escapes the corners of his lips. It's uncomfortable, it's humiliating and it's got him so hard. He loves it.

"Not so confident without your quirk are you?" Iida's voice is soft but loaded, dangerous.

Dammit, he's right: without the power of speech, Shinsou is putty in Iida's hands. He narrows his eyes at him, almost willing himself to talk, but the ball sits hard against his tongue. Any sound he could try and make now would come out as a gurgle, especially with the plug still sitting snugly inside him.

Until now, Iida has been pacing the room, but he stops in front of Shinsou, gazing down at him.

"Maybe I should just leave you like this..."

In the back of his throat, Shinsou whines, the sound weedy and pathetic even to his own ears as Iida moves behind him.

"Oh I'm sorry, does the slut have an opinion?"

Holy shit.

Without warning, Shinsou feels a swift shove between his shoulder blades and he lands on the floor, face down, ass up, totally on display. His cry of surprise seems not to bother Iida in the slightest; he kneels down behind him and tugs on the end of the plug. The stretch of it makes Shinsou let out a strangled moan, his body shaking with anticipation as it's pulled out. Iida fingers him briefly, less out of necessity and more to tease.

"How does it feel?" Iida asks, his voice still as smooth as silk over the sound of him unzipping his trousers. "How does it feel knowing I can do whatever I want to you?"

Shinsou groans. It feels fucking amazing and Iida knows it. It doesn't take much longer before Iida sinks inside him, filling him and drawing another desperate moan from him. Saliva runs down to the floor, the angle of the ball gag letting it escape; in any other circumstance Shinsou would try to clean himself up but with his arms bound he can't. Iida starts thrusting fast and deep, gripping Shinsou's hips hard enough to bruise.

"You clench around me so much more when I gag you," he growls. "You secretly love it, don't you?"

Shinsou can only whine in response—it's not a secret, not really: Iida knows how much he loves it. His thrusts grow harder, making Shinsou's thighs tremble with the force and effort of keeping himself from collapsing, and finally, blissfully, Iida's hand reaches down to stroke his cock. He shudders, eyes rolling back, and hears Iida give a low chuckle behind him.

"You going to come, slut?" he asks. "You going to come on your knees with a gag in your mouth?"

His orgasm rips through him, making him cry out through the gag; he barely even notices Iida coming moments later. Iida fucks him through it, hand stroking him steadily until he's a trembling mess. When Iida finally slows his movements to a stop and pulls out, his legs give out and he flops, only kept from collapsing onto the floor entirely by Iida's strong arms wrapping around him.

"I've got you," he says softly, leaving a kiss to Shinsou's shoulder. "You did so well."

The gag comes out, dropped to the floor with a wet thud, and Shinsou flexes his jaw to get the feeling back. Once the handcuffs are off too, Iida scoops him into his arms, pressing a kiss to his forehead, and carries him through to the bedroom.