Tony is staring again. He should probably look away before Bruce notices, but he isn’t going to. Not when Bruce’s pretty pink perfect mouth is slip-sliding around phrases like “thermal flux actuator” and “modulated particle array” and, fuck, did Bruce just lick his lower lip? The man is a safety hazard brought to life. He shouldn’t be let loose in a lab except of course he should because the lab is where Bruce was made to be. Well, restraint isn’t Tony’s strong suit at the best of times, and in the face of such temptation is not the best of times.
So he keeps staring at Bruce’s mouth, even as he shifts his hips to try and find some relief, which is somewhat counter-productive because Bruce mentions the oscillating warp harmonic and, yes, Tony is most definitely incredibly turned on. He shifts back on his stool and spreads his legs a little. It flits across his mind that this might not be the best idea to jack off in front of his newly discovered friend/housemate/resident rage monster, but Bruce gives him an awkward half smile and the thought of not doing this is gone forever. This is happening.
Tony finally manages to wrench his gaze away, if only for a moment. He shifts the hammer (because he is an engineer, damn it, and he is much much sexier when holding tools and he considers it a small act of vengeance because, seriously, that mouth) he’s been holding from one hand to the other, and oh-so-casually drops his hand into his lap and works his jeans open. He grins fiercely as he wraps his hand around his cock and identifies the flaw in Bruce’s proposal.
Bruce worries his lower lip gently as he considers Tony’s objection, and Tony wouldn’t even know where to start on the list of things he wants to do that mouth, the things he wants it to do to him. With a slow stroke, he decides that listening to Bruce think out loud, hear the first draft of those fucking beautiful notes would probably right at the top of the list. He shines like the fucking sun when he talks like this, impossibly brilliant and, oh, Tony loves the back and forth when they argue. They create beautiful harmonies of point and counterpoint, finding an easy rhythm. The tempo increases as they pick holes in each others theory, as they offer new theories, as they try something completely different, and then there is the beautiful climax when they figure it out, all manic smiles and too fast hands and perfection. Tony recognises the obvious symmetry, because of course science is a metaphor for sex; there are days when he can barely tell the two apart.
He traces the vein running along the underside of his cock, almost whimpering at the drag of his calloused finger. And Bruce grabs the water bottle beside him for a quick swig. And, oh yeah, maybe listening to the first draft of his notes can be moved down the list. Tony’s eyes flick down to the line of his throat, to the movement of his Adam’s apple and there are definitely other ideas about what he wants Bruce to do with his mouth. It would be hot and wet and he has to bite off the moan that threatens to break through because the image of Bruce’s lips stretched around his cock, maybe a bit of precum and spit leaking out the corner of his mouth is too much to keep properly locked down.
Bruce looks at him with a flash of concern as Tony puts the hammer down on the bench. His hand doesn’t even tremble as he rests it on his thigh or as his fingers grip the denim. “Are you okay?” and he wrangles all his self-control and grins.
“I’m fine, Jolly Green. Tell me all about how you plan on magically not blowing me up with these suggested changes.” Bruce pulls a face and Tony grins even harder because he knows there is a magic combination of words that will get Bruce to stick his tongue out at Tony and Tony will probably weep with gratitude and joy when he finds it.
He twists his wrist on the downstroke, and his hips twitch up. Deep breath. Bruce was revising his theory, offering new suggestions and Tony can see the way he runs the scenarios in his head. He can tell by the way Bruce purses his lips that he exploded in that scenario, but he can’t quite make himself focus on his hypothetical fiery death when he is imagining lickingbitingkissing those beautiful lips. And yes, he is mentally reordering that list again because Bruce is an amazing kisser. Tony can tell by looking at him. He knows these things.
He picks up speed, contemplates the image of Bruce’s mouth hot against his neck. He could leave a mark, Tony wouldn’t mind. He would the opposite of mind, actually. He would wear it with pride, it and any other marks Bruce left behind. Bite marks, scratches, a scatter plot of fingerprints at his hips. Fuck. Tony would happily let Bruce cover him with marks, turn him into a walking talking piece of art. He would be a great human canvas, and all he would ask in return is the right of response because he has seen Bruce’s collarbone and it needs a hickey on it just as sure as Tony needs oxygen.
“Really, are you alright, Tony? You look a little flushed.” He leans across the bench, reaching to touch Tony’s forehead and of course he sees exactly what Tony is doing. “Oh.” He starts to pull away and Tony can’t help but lean forward trying to follow him. “I should, um - I should go.” And there it is again, his tongue darting out, brushing over his lower lip, and it is wet and shiny and Tony curses.
“Keep talking, please. Keep talking about the shielding technology, your ideas for my repulsors. Fuck,” he whimpers as he drags his thumb over the head of his cock, spreading the slick of precum. He should have a shiteating grin and a smart comeback ready for this, but he is so close and Bruce looks more intrigued than horrified. Everything he has is straining towards the orgasm that is curling and creeping through his body and even Tony has his limits.
Bruce, beautiful terrible wonderful Bruce, smiles. And scratch the earlier drafts of the list, that is the thing he most wants Bruce Banner to do with his mouth. “Need a hand?” he says, walking around the bench towards Tony, and Tony can’t help but laugh because seriously? That might actually be the cheesiest thing he has every heard.
The laugh is cut off with a sharp gasp and a hissed yes when Bruce grabs Tony’s wrist, pulls his hand away, and replaces it with his own. “Yes, yes, yes,” Tony chants, thrusting up into Bruce’s fist.
Bruce tangles his other hand in Tony’s hair and pulls him close, so close, resting his forehead against Tony’s. And Tony positively whines at the fan of hot breath against his lips. “May I?” Bruce asks, quiet and rough, and Tony nods and the kiss is tentative until Tony’s mouth falls open and he moans shamelessly. And, Christ, in between kisses and bites and gasps, Bruce tells him about how he is going to use the magnetic warp capacitor to improve his repulsors, and he just needs to figure out how to stabilise the thermal interface harmonic and Tony is rutting shamelessly against him, begging for more.
Too soon he can feel orgasm unfurling, the relentless tightening of his muscles, the spiralling tension coiling white-hot in his groin. The air is torn from his lungs in a ragged groan as the tension finally crests and breaks. Bruce keeps stroking, ringing every last ounce of pleasure from him, still murmuring kisses and words against his lips, and Tony is never going to let him go. That’s it. He is keeping Bruce, because that needs to happen again. That needs to happen again a lot.
He cracks an eye open to look at Bruce, who looks shocked and pleased and desperate. Tony grins. “Need a hand? Seriously?”
Bruce flushes. “It sounded smoother in my head,” he says, a sheepish grin playing at the edge of his lips.
Tony kisses him; it is soft and indulgent even as he palms Bruce’s cock through his pants. “We need to do something about that,” he whispers.
“We really do. Did you have anything in mind?” Bruce says, and he sounds wrecked, right on the edge and ready to jump.
“I have a list,” Tony says, sliding off the stool to stand pressed against Bruce. “But I am going to start with this,” he murmurs, easing Bruce back a few steps and dropping to his knees.
“I- Yes, okay,” Bruce breathes, and at some point he will have to untangle his hand from Tony’s hair and that will be a tragic day for all involved.
It doesn’t take long - Tony hollows his cheeks and sucks for all he is worth (and he is worth a goddamn lot) - and Bruce’s fingers clench in Tony’s hair, his head falls back, and he comes in a rush.
And there are things that are going to need to be said because Tony can feel in his bones that Bruce will try to run because Tony can’t possibly love him and some New Agey self-esteem bullshit and blah blah blah, but that is a problem for later. Right now, he accepts the hand Bruce is offering to help him, pulls Bruce into a fierce kiss, then drags him up to his room.