Bucky is balls deep inside Steve, his arms tight around the other man’s body from behind when he hears it. Over the loud slap of skin on skin and their mutual grunts and moans, Steve is drawing in ragged, short, wheezy breaths like when he used to have asthma. Bucky freezes immediately, only then realising how tightly he has his metal arm wrapped around Steve’s neck, cutting off his air supply. He’s been so lost in pleasure it took God knows how long for the sound to penetrate his lust fogged brain.
“Jesus, Steve, I’m so sorry!” he pants, loosening the grip with his metal arm. He takes half a step back, intending to pull out and turn Steve around to face him so he can see that the other super solider is really okay, but Steve’s hand clamps down like a vice around his metal wrist, holding him in place.
“No,” Steve says in an urgent voice, using his own strength to pull Bucky’s metal arm back to where it was, “I...like...it,” he gasps.
Bucky shakes his head, the words not sinking in straight away, “What? How can you like it when...when you used to…” his mind drifts back to all those times before the war when Steve was up at night, wheezing and coughing in the cold winters. Numerous times the older man was terrified that one of those shaky, wheezy gasps might be Steve’s last. He was so weak and fragile and it always broke Bucky’s heart.
He’s brought back to the present by Steve reaching behind them and grabbing a handful of Bucky’s ass cheek and pulling him in closer. “Buck,” he says, his hand slamming into the wall so he can get enough leverage to angle his hips back and grind himself further onto Bucky’s cock, “c’mon, I can take it.”
A hot surge of lust burns through Bucky as he realises it’s true. Back then, Steve got out of breath from walking up a flight of stairs, but now the man in his arms is far from fragile and absolutely can take whatever Bucky gives him. The older man’s hips snap forward of their own accord, causing both of them to groan as Steve is entirely filled.
Resting his forehead between Steve’s broad, sweaty shoulders, Bucky releases the grip his flesh hand has on the blond’s cock and slides it over his tight stomach and abs, up to Steve’s left pec and squeezes, putting extra strain on his lover’s already struggling lungs.
Steve groans and moves to take himself in hand, but Bucky’s having none of it, “Nuh uh,” he growls, “you want this, you’re gonna come untouched, understand me, punk?
Steve nods as best as he can, then makes a sound that’s half whimper, half gurgle as Bucky thrusts and angles his hips just so, nailing the other man’s prostate with expert precision. Steve’s hand momentarily covers Bucky’s flesh hand before dropping down to his side, then gripping his own thigh to keep from touching himself.
“Good boy,” Bucky coos, slowly drawing his cock out of Steve until only the head is inside, teasing like he knows Steve loves, “now tell me what you want. Say the words, Cap."
Steve lets out a half sob at the words and squeezes his ass around Bucky’s cock in an attempt to keep it inside of him, but doesn’t push back - he knows better. Out there in the world, Captain America might be the one in charge, the one giving everyone else orders, but when it’s just them there’s no doubt who calls the shots, and they both get off on it.
Steve’s sweaty hand slips on the wall before he rights himself again, opening his legs wider for better balance, “Oh God,” he gasps, shakily, “fuck me...choke me...shit, I’m so close, please, Buck.”
That does it, Bucky’s never been able to deny Steve anything when he gets desperate like this, “Fuck, Stevie, you beg so damn pretty for me. Gonna give you what you want,” … and he does. He sets an unrelenting pace, fucking Steve with long, hard thrusts, his grip never faltering around the other man’s throat as Steve really does take everything Bucky gives him.
He can’t be sure, but Bucky thinks that the clicks and whirs of the metal plates moving into place as he adjusts his arm to squeeze as tight as he dares, is what pushes Steve over the edge. His whole body goes taut, his inner walls clamping down hard around Bucky’s cock as he comes hard all over himself, the wall and both Bucky’s flesh and metal forearms.
It’s all too much for Bucky after that and he moves quickly, his metal arm releasing Steve’s throat and letting precious oxygen back into his lungs, before moving to Steve’s shoulder and all but slamming him into the wall to hold him there easily. He moves his hips with even faster, even more brutal thrusts until his own breath is almost as ragged as Steve’s, groaning loud and deep as he comes hard inside his lover.
Their harsh breathing is the only sound that fills the room for a few minutes, followed by a mutual groan of loss as Bucky’s cock finally softens and slips out of Steve’s ass. Bucky releases the blond enough so he can turn around to face him and braces his arms on the wall at either side of Steve’s head. They kiss wet and dirty until both need to pull away to breathe - they might both be super soldiers but they do have their limits.
Steve places one hand over Bucky’s pounding heart, the other the nape of the older man’s neck, his fingers stroking through the sweaty hair, there. “We are so doing that again,” Steve says, his voice strained and gravelly, and fuck that’s sexy, Bucky thinks.
When he manages to drag his eyes away from Steve’s fucked out face, he sees the angry purpling bruises around his neck, the perfect imprint of the metal plates from his arm clearly visible.
“Shit, Steve, did I hurt you?” he asks, using his flesh hand to brush a thumb over the tender skin. Steve gasps, and Bucky’s momentarily worried that he’s really hurt Steve until he looks back up to see pure renewed lust in those beautiful blue eyes. His own breath catches then, taken by surprise as Steve reverses their positions, slamming Bucky into the wall. He leans in close and grinds his hardening cock against the other man’s thigh, while he presses a forearm under Bucky’s chin with slowly increasing pressure.
"Your turn,” Steve whispers, before kissing Bucky breathless before they start round two.