@winterironmonth prompt - NSFW Saturday: Trope/Kink, Word
Trope/Kink: Size Difference
I’ve written omega/omega, now I’m gonna try alpha/alpha I think. Also Tony would react this way to anyone he thought loved him which is probably very sad, but Bucky isn’t going to think about it too hard right now because he wants to enjoy the gift that is Tony’s trust. Was gonna shove in some more size difference but didn’t want to write foreplay lol right now lol. Don’t forget to blacklist ‘long post’ and ‘lemon’ if you don’t want to see it!
Their ruts rarely coincided. It had only happened once before, at the beginning of their relationship, when it was too new to spend together even if they hadn’t both been alphas. Since then, it had been one or the other, with the non-rutting partner taking the place of the ‘omega’ for the coupling. They’d synced up again, though. Bucky had worried they might attack each other, both of them flooded with hormones like this. Tony wouldn’t have stood a chance—or he’d call the suit, and then Bucky wouldn’t have.
He shouldn’t have worried. Tony had lunged for him with a snarl as soon as he’d seen him, but he hadn’t summoned the suit, and Bucky hadn’t felt the need to engage the metal arm. It had seemed… fun, almost, wrestling for dominance. Tony had thrown a few punches, but Bucky had blocked them easily, and then he’d gotten Tony pinned, his larger body covering Tony’s easily. And while Tony had snarled and thrashed as Bucky had lubed him up, stretched him for a knot, now he was soft and sweet, eyes half-lidded as he stared up at Bucky, lips spread into a wide, fuck-drunk smile as Bucky ran a hand over his bloated stomach.
“Good?” Bucky managed to grunt. Tony hummed, sounding very pleased, but that was the only answer he got beyond Tony’s sticky thighs spreading a little wider. Bucky couldn’t help the guttural growl that escaped him at the motion, tightening his grip on Tony’s wrists as he fucked into him harder. “Gonna knot you again, doll.”
“Knot me,” Tony echoed dreamily, arching his hips up, as if this wasn’t the fourth knot Bucky was stuffing into him.
Bucky let go of his wrists to clutch at Tony’s hips, tipping them up for a better angle as he pounded into him, knot butting up against Tony’s swollen rim with every thrust. He couldn’t help another guttural growl as Tony’s thighs fell open wider, as if he was simply a doll to be moved around for Bucky’s pleasure, a perfect omega hole for him to breed despite not smelling of any slick. Tony’s cock even had a bit of a knot forming where it was bouncing against his rounded belly.
Bucky adjusted his grip so that Tony was braced properly, then shoved deeper, knot catching, stretching, pushing. Tony let out a broken little sound, just this side of distressed. Then the noise turned into a guttural groan as Bucky’s knot shifted further, past the resistance, and his body sucked it in deeper, locking it in tight. He trembled, overwhelmed, even as his hips rutted to helplessly chase after his own orgasm. Bucky leaned down to kiss his gasping mouth and finally released one of Tony’s hips to wrap his fingers around Tony’s cock, stroking it gently until Tony was whimpering into his mouth. Then he slid his hand down further, curling his fingers around Tony’s knot and giving it a squeeze, tightening his grip until Tony’s hips jerked and he let out a broken little hiccup as he came.
Bucky collapsed on top of him as if his strings had been cut, mouthing at Tony’s throat, catching with his teeth. “Doing so good for me,” he finally managed, because Tony was, so open and sweet for him, taking knot after knot.
The serum gave him a shorter refractory period even when he wasn’t in rut, but Tony took it like a champ, insatiable, almost ravenous in his desire to be filled whenever Bucky was on top. Tony was always generous, no matter what position they were in, but he seemed even more willing when Bucky was curled on top of him, protecting him from the world with the bulk of his body.
Tony started kissing him back after a while, lips trailing over his forehead and cheek where he could reach without having to move much. Bucky lifted his head to kiss him on the mouth, slow and soft, before finally breaking it again to carefully lean back, giving him a little breathing room.
Tony blinked up at the ceiling, languid and satisfied. Finally, he let out a little sigh and huffed, “Full.”
Bucky couldn’t help a smile, rubbing a hand down Tony’s bloated stomach again. “Nice and round for me.”
“Full,” Tony huffed again, and this time it sounded like a complaint.
Bucky pressed another kiss to his mouth, then mumbled, “I’ll get you to the bathroom before I tug my knot out and we can relieve some of that pressure, yeah?”
Tony offered him a short nod, but that was it. His hand drifted down to cover Bucky’s on his stomach. He let out a quiet mewl when Bucky pressed down lightly, frowning. “Ngh.”
“Bet you’d give me a pup every heat with how well you take it,” Bucky said, smiling a little.
“Fuck off,” Tony mumbled, rolling his eyes. Then he paused, brows furrowing together as Bucky ran his hand up and down his stomach again. “Well. I mean. Of course I would. I’m the best at everything.”
“Including being humble,” Bucky said, smile growing. He began to sit up, so he could adjust his position.
Tony wrapped his arms around his neck quickly, pulling him back down with a muted whimper. “No.”
“I’m not going anywhere, doll,” Bucky assured him, arms coming up to wrap around him. “I’m just cramping a little. Wanted to adjust.”
Tony made another noise of distress and cuddled closer. “I can… Please.”
Bucky pressed a kiss to the side of his head. “Okay, okay. Here we go. Hold onto me, doll.”
Tony clung to him tightly, whimpering as Bucky carefully took his weight and turned so that he was the one on his back, laying Tony down across his chest carefully. “Ugh, full,” he moaned, letting go of Bucky to push himself up a little.
Bucky took the opportunity to push himself up the bed and get himself into a seated position against the headboard, cradling Tony against his chest again. This time, he got a pleased sigh, which he rewarded himself for by nosing at Tony’s swollen bonding gland. “Wanna bite you so badly,” he moaned, hands running up and down his back.
“So do it,” Tony said simply.
Bucky froze, stunned at the offer. It was dangerous for an alpha to bite another’s bonding gland, no matter how much they loved each other—it would release a rush of hormones that caused them to be even more protective of their omega and attack any interloping alpha they scented. Some couples managed it, but it was only after years of love and trust. Tony and Bucky had only been going together a couple years, and they both had their own trust issues. He couldn’t imagine biting him and having a good outcome.
But now he also couldn’t imagine not sinking his teeth into the swollen gland, Tony’s arms around his neck, belly swollen with his spend.
“What if we…” Bucky began, hands clutching at Tony’s hips tightly. “We’re tied. I don’t want to start anything…”
“You held me down once,” Tony pointed out. “I won’t bite back, if you’re worried.”
That wasn’t what he was worried about at all, but Tony sounded so reasonable… “Still…”
Tony leaned back to raise his eyebrows at him, as reckless as he always was as he put his hand on his stomach and indignantly asked, “You’re not going to bond with the other parent of your whelp?!”
“You’re not an omega,” Bucky said, but a growl was welling up in his chest at the thought, eyes darting down to Tony’s hand and then back up. “Tony.”
“It will be fine,” Tony promised, and he sounded so sure about it.
Bucky leaned in and nosed at the gland again, mouth watering at the idea of biting into it. He shouldn’t. So much could go wrong. But then, it could have gone so wrong at the beginning of their ruts, too. He ran his tongue along the gland gently, consumed be the taste of sweat, the tang of sex heavy in the air. He felt Tony shiver and couldn’t help allowing the growl to bubble up, possessive and wanton as he pressed his teeth to the skin, waiting for Tony to flinch or growl back.
Tony did neither, instead tipping his head back to give him more room to work with. “Bucky…”
Bucky sank his teeth in before he could even think to stop himself, clutching Tony to him, ready to grab him and hold him still if he tried to attack. He needn’t have worried, though, because Tony’s only response was to stiffen, then fall limp in his grip with a whimper, cock twitching between their stomachs. Bucky groaned, mouthing along the gland a little longer, then leaned back, looking down between their bellies to see Tony’s cock hard again. “You like that,” he said, surprised, then growled again, tipping his head back to give Tony a sharp smile. “Your neck is gonna look like a chew toy by the time I’m finished with you.”
“I still wanna go to the bathroom before your next knot,” Tony said, letting his head loll to the side again in offering. “I might actually puke if you put another load in me with all this mess.”
“As long as I can keep sucking on your bonding gland, maybe we can put your dick in me once or twice,” Bucky offered magnanimously, before he latched onto Tony’s neck again, worrying at it with his teeth. “Once the hormones wear off a little more.”
Tony jerked in his lap with a surprised moan, leaning more of his weight against him. “Oh… Yeah, sure…”
“Fuck, that’s so hot,” Bucky groaned against his throat. He had the thought of offering up his own bonding gland to Tony, but he didn’t trust himself as much as Tony apparently did. He didn’t want to even think about what might happen if he reacted badly. He reached down to wrap his fingers around Tony’s cock. “Gonna come again for me?”
“Keep your mouth on my neck and find out,” Tony purred, as if he wasn’t the one who was putty in Bucky’s hands.
It was truly unfair that Tony could manage to sound like he was in charge and in control when he was stuffed full of cock and limp in Bucky’s arms. Bucky doubted he’d ever be so articulate in the same position. “So unfair,” Bucky mumbled to himself, before he adjusted his grip and started stroking Tony in earnest.
