It isn't that Tony doesn't like Bruce.
Bruce is the first intelligent person Tony has met in years, and Nick Fury and his not-so-merry band of secret-mongers might have a vague notion how useful a mind like that could be to them, but Tony doesn't think... No, Tony knows, from the way they look at him when he's working with Bruce, the way they search his statements for irony and his punchlines for malice, that they have no clue how rare a mind like Bruce Banner's is to someone like Tony, how bright it shines – like fireworks and Christmas lights and long weekends in Vegas come early – in all the parts of the spectrum most people's brains aren't calibrated to perceive. They don't see what Tony sees, but, yeah, no, he supposes that's still not one for the eleven o'clock news.
Pepper sees it, though. Pepper is smart like that, has always been. Which is probably why the “Tony, you didn't really think I entered into a relationship with you expecting us to be monogamous?” talk didn't, in the end, happen because of any of the many and various lingerie models and wannabe starlets and waiters at that great seafood restaurant on 4th Tony may have flirted with since their thing became a proper...thing, but because of an unassuming, rather average-looking scientist who's helped him save the world a couple of times and laughs, almost inaudibly, at his jokes about quantum entanglement.
So, yeah, Tony does like Bruce.
On afternoons like this one, laid out on Bruce's bed in what used to be Stark Tower and has now somehow ended up The Tony Stark Home for Wayward Superheroes and Lost Deities from Parallel Dimensions, face down and ass up and thighs spread as far as they will go for Bruce to kneel between them, while the computer in the lab down the hall runs a simulation that's going to spit out the answer to the latest absurd problem SHIELD has decided to throw at them... On afternoons like this, he really likes Bruce a hell of a lot, is what he's saying.
The thing is, though, he's never made a secret of the fact that he also likes the other guy. The big green guy who is Bruce done up in his suit of armor, ready to rumble. And, okay, most people seem to think he's trying to be funny when he says that he's a fan of the Hulk, that he's been a fan since the first time Coulson brought him video footage and he couldn't take his eyes off the explosion of power he saw on the screen, but Bruce is pretty much as far removed from most people as it's humanly possible to get. Bruce was always going to catch on.
Which is why he doesn't even bother to pretend it's a non sequitur when Bruce leans over him, stroking his palm up the backside of his thigh, and says:
“So what is the attraction for you, Tony? The monster aspect? The strength? The size?”
Bruce punctuates the question with a lick at the curve of Tony's spine, hard cock dragging against his ass, and Tony gasps, hips angling back for it. Bruce isn't exactly small, even like this. Tony can't help trying to imagine what that means for the Hulk, what the proportions might be. After all, scientific curiosity is what got him where he is today.
“Maybe I just find the color green irresistibly fetching?” he suggests. “Green jello, always my favorite. Emeralds, very sparkly. Grass. Grass is nice. Highly...photosynthetic.”
Bruce breathes out a laugh against his shoulder, but his hand on Tony's leg squeezes down, pushes forward, pressing his knee further up towards his chest.
Bruce is kind of implacable. People think because he doesn't like to argue he can be pushed where they want him to go, but the truth is he's one determined son-of-a-bitch. That he doesn't like to argue just means it's hard to derail him. Or distract him.
“You're so small to him, Tony,” he says. “I'm pretty sure he could wrap his hand all the way around your thigh. Bend you any way he wanted.”
His voice is soft, calm, like he's making an observation based on numbers on a graph in the lab. Tony's chest feels too tight, his fingers digging into the sheets above his head.
Bruce leans away from him, and then there are his fingers, wet with lube, stroking over Tony's hole. Working their way inside. For a minute, neither of them says anything, beyond the noises of pleasure Tony makes at every stroke to his prostate, the way Bruce's breath hitches whenever Tony squeezes tight around him. It's good, it's so good, and Tony has almost forgotten they were having a conversation when Bruce says:
“A single one of his fingers is thicker than my cock. How many do you think you could take?”
Tony's entire body shudders, his hips shoving back, slamming Bruce's fingers deeper. He has to remind himself how to breathe.
“Fuck, Bruce,” he grits out. “Warn a guy.”
With his neck bent, his forehead buried in the pillow – he can't breathe, Christ, he's so hard – he can't see the slight quirk of Bruce's smile, that gentle brush of amusement that's so beautiful, there and gone again, but he can hear it in his voice when he just keeps talking.
“Come on, Tony, don't say you haven't thought about it. You always want more, don't you? More speed, more thrills, more explosions. More thoughts, more ideas. More sex.” His fingers are rubbing steady circles on Tony's prostate, his other hand stroking his flank, the small of his back. But it's the words, the images he's putting in Tony's head that are driving him out of it. “How many do you think? Two? Three? You would try for three.”
He can imagine it, how full he would be, how he'd want to be fuller, want more. And the Hulk is more of fucking everything. Bruce is, with all the gorgeous stuff inside his head. All of Bruce, the totality, is more than Tony ever thought to ask for, and he wants it, wants it in ways he doesn't even know how to articulate.
Although Bruce is doing a pretty decent job of articulating some of it for him right now.
“He wouldn't know how to go at your pace, though, would he?” he says. “He's just a beast, just brute force. He wouldn't understand that you'd need preparation.” He pulls his fingers out, and Tony whines at the loss of them. He doesn't want to be empty. It's like that weightless, hollow feeling in his chest when he takes the arc reactor out; the slight edge of panic he always feels, even when he knows he's going to put it right back. But then Bruce is on top of him. Bruce's hand between his shoulder blades, urging him down, urging him still. Bruce's cock against his opening, a thick, blunt pressure. “He'd push you down,” Bruce says. “Simply take you.”
Tony can almost feel it, the hand between his shoulder blades large enough to span the width of his back, heavy enough to keep him trapped. Helpless.
“Yes,” he says. “Give it to me. Come on, Bruce, you know I want it.”
Bruce makes a soft, strangled noise, and slides in. One long, forceful shove, all the way inside, pushing the air out of Tony's lungs as he goes. Then he holds still, buried balls deep in Tony's ass, draped over his back, breath shallow and moist against the crook of Tony's shoulder. He's still wearing his glasses – Tony can feel the edge of the wire rim, cool against his neck where Bruce's cheek is hot, overheated. It's unforgivably dorky, and so viscerally sexy it makes his balls clench. He gets a hand up, despite the awkward angle, reaching behind him, and pats at Bruce's hair, all those soft curls. Sinks his fingers into them, nails scratching at Bruce's scalp.
Fuck, he likes Bruce. Just like this, just the way he is.
Except then Bruce turns to brush his lips against Tony's wrist, and says:
“You really do want it, don't you, Tony? Want him? I bet you've thought it all out, how you'd get his cock inside you?”
Tony's hips stutter, his insides squeezing tight around Bruce's dick, around the perfect, solid thickness of it filling him up. Bruce's body moves in response, starting to fuck him.
“Yeah. Yeah, I...” Slow, shallow thrusts, right there, right there, and his voice sounds choked, low and broken, but he keeps talking. “Engineering problem. Small hole, large peg. You know me – can't stay away from the tricky equations.”
Bruce huffs, something that might be a laugh, but he's breathless now, fucking Tony harder. It's difficult to tell.
“And your solution?” Bruce says.
Tony closes his eyes.
It's never going to happen, he knows that. It's Bruce's greatest fear, transforming and hurting someone he...someone who... He would never risk that. But just having him ask.
“I'd have to work up to it,” Tony says. “For days. Maybe weeks. Stretch myself wider and wider. I...” It's embarrassing, saying it out loud, but he's always been eager to do what others find shameful. And just the thought of this makes his cock drip, his nipples ache. “I already bought the largest toys I could find. But I don't know exactly how big he is. I might have to make my own, to bridge the gap.”
“Tony,” Bruce says, and there's no reading that tone. The movement of his hips, though, the smacking sound of his balls slapping against Tony's ass as he thrusts in hard enough to shove Tony a few more inches up the bed, Tony can read that just fine.
“Think about it, Bruce,” he says. “The largest peg you can imagine, and I'd have to carve the mold myself, melt the silicon to cast it. I'd be half hard the entire time. And then working it inside me. So deep. I'd make myself wear it all day, make my body accept it, love it. But I'd hardly be able to move, hardly able to think, it'd be so big. But the best thing...” He swallows, his fingers tight in Bruce's hair, now, clinging. “The best thing would be knowing that he would be bigger. You would be bigger.”
Bruce makes a noise that is somehow both growl and whimper, gorgeous in Tony's ear. He's fucking Tony so hard; long, deep thrusts that are pulling him apart. Tony can't get enough of them, could lie here forever, just being pounded open. Having Bruce pound him open.
“When I thought it was time,” he says, because he wants to say it, wants Bruce to hear. “I'd take you somewhere safe, deserted, just you and me. And I'd find a way to make you...have an incident, make you... Bruce.”
Bruce is trembling above him, panting as if his lungs can't catch enough air. He's stopped moving, holding still on an out-stroke, barely inside Tony at all.
“You didn't solve for all the variables,” he says at last. “You can't know what he would do. There'd be no control, no restraint.” He pauses, and Tony can hear him considering, the background noise of his brain working that's always there, like the spinning of a finely tuned engine, making the air crackle whenever he's in the room. “But maybe you don't want a solution to that. Maybe that's the real attraction.”
“First rule of engineering,” Tony agrees. “If it isn't broken, don't try to fix it.” And he means it, like he meant it that first day on the helicarrier, like he's meant it every day since. The Hulk isn't, Bruce isn't broken. He's everything awesome, wrapped in one outrageous package, and Tony's never wanted the safe things, the dull things. He's always wanted most the things people said were too dangerous to play with. “Come on, Bruce,” he says, and he's rocking back, his body moving because it has to, trying to get more, trying to fuck himself on Bruce's cock. “I'm close here, buddy, I need some friction. Come on.”
“High maintenance,” Bruce mumbles, but it mostly sounds fond, so Tony chooses to ignore it.
Besides, there is friction. Quick, jabbing thrusts now, none of Bruce's usual patience, and when Tony arcs his back, every stroke hits his prostate, and he could come, almost, almost, just from this.
He won't have to, though, because Bruce slides his hand down his flank, over his belly, down to close his fingers around his dick.
Tony groans, a wordless, desperate noise. Bruce's hand doesn't move, simply stays there, holding him.
“You know,” Bruce says. “I used to wear a pulse meter. For a while, I did that. Trying to read the physical warning signs, to calm myself down before things got away from me.” His thumb strokes over the head of Tony's cock, the touch too unbearably soft. Tony is shaking. Bruce is, too, Tony can hear it in his voice. “It had an alarm that started going off at one-forty. That's when I was too close.” Bruce's hair is damp with sweat where Tony is still touching it. The strain in his arm is making his muscles twitch, but Tony can't seem to let go. “JARVIS,” Bruce says, raising his voice a little. “What is my current heart rate?”
“One-hundred-and-eighty-eight beats per minute, Dr. Banner,” JARVIS replies, without hesitation.
Tony breathes out.
He isn't even sure if it's that Bruce just addressed JARVIS in the middle of sex as a matter of course, or if it's the implications of what Bruce just told him, but his balls are so tight his vision is blurring, and his cock is jerking in Bruce's fist, dribbling over his fingers.
“Yeah,” Bruce says. “That's how close he is. Every time I'm with you. I should stop, Tony, but I can't. I don't want to, when you're so eager, when you feel so good. Fuck, I want this, Tony.” His hand squeezes down hard on Tony's shaft, twisting. “I want this, even though he could come out at any moment, could tear free, while I'm still inside you. Tony.”
Tony's orgasm feels like a vertical dive in the suit from three-thousand feet, feels like the shock of the turn when he levels out a couple of inches from the ground. He feels Bruce coming with him, riding the shockwaves through his body, burying his face in Tony's neck and holding on, as their heart rates spike, as their bodies shake and sweat and stay the same.
When Tony finally uncurls his fingers from Bruce's hair, he can barely move them.
Tony throws the towel he's just used to clean up with towards the foot of the bed and flops down next to Bruce on the pillow. He runs his fingers through the sparse hair on Bruce's belly, watches idly as his hand rises and falls with Bruce's breathing.
“I feel I should say this, because for some reason people tend to jump to conclusions when it comes to my ability to respect boundaries,” he says, “but I would never actually induce a Hulk incident for sex.”
Bruce makes an amused noise.
“I know that, Tony.”
“Unless you asked me to, of course.”
Bruce is silent for a beat too long.
“'Of course'?” he says. “You like him that much?”
Tony sits up sharply, twisting to glare down at him.
“Honestly. You need to hand me your membership card in the Supergenius Club right now, so I can tear it up on behalf of supergeniuses everywhere. I like you that much. All of you.”
Bruce blinks up at him. His glasses are still on, slightly askew. Tony can see the smudges on the lenses from his own skin. Bruce licks his lips. His hand reaches out, strokes up Tony's forearm.
“Tony,” he says.
Tony has no response for the tone in his voice, but he wants to kiss him.
“Dr. Banner,” JARVIS says. “Your computer simulation has completed.”
Bruce's eyes squeeze shut, then open.
“Okay,” he says, sitting up, the top-sheet pooling in his lap. “Can you display the results here, JARVIS? Start with the projected ionization numbers.”
A screen with the relevant figures appears in the air above the bed. Bruce gives an interested hm and leans forward to look closer. Absently, he straightens his glasses. His other hand is still touching Tony, thumb stroking across his knuckles.
Tony shifts closer, the better to read the numbers over his shoulder.
The thing is, he supposes, like he just said: he really likes Bruce.
No qualifications needed.