Bruce understands fear, and he understands hatred of losing control, so he also understands perfectly well why Natasha wants to have sex with him. He's her bogeyman, the monster under the bed, the strange noise in an empty house. The difference, though, is that he's real, and he does hurt people, so it's not a bad idea for most people to be afraid of him. Natasha, like everyone else on the team, isn't even close to being like most people.
She ran from the Other Guy once, and she won't do it again, though it's unlikely she'll ever need to at this point. But not running isn't enough for someone like her—she won't be happy until she's pushed back at him, shown him she's not afraid, proven she can handle him.
Bruce is okay with being handled.
"Can you do this?" she asks, straddling his thighs. They're on his bed in his new apartment at Stark Tower, in the middle of the afternoon. She's been here ten minutes and they're already mostly naked.
"Oh, I can do this," Bruce murmurs, as he slides back a little until he's propped against the headboard, urging her to follow with a hand around the back of her bare thigh. He wouldn't have let her in, or let this go as far as it already has, if he thought he couldn't deal with it. He's learned a lot about control since the last time he was in New York.
When she settles over him he tugs the delicate edge of her bra down just enough to close his mouth over one pink nipple, already hard before he even touches it with his tongue. She says something in Russian that is probably encouragement, based on the way she grabs at his head and arches her back. He works at it for a little bit, getting it nice and sensitive, before he switches his mouth to the other side, leaving his thumb to circle what he's wet with his mouth.
"Adrenaline rush," she gasps, grinding down against him. He's been hard since he opened the door and let her in. "Accelerated heart rate."
He makes a pleased hum against the soft skin under his mouth. Natasha's done her research: she knows both the basics of human sexual response and Bruce's triggers, and just how many of them overlap. He wouldn't expect anything less.
"I can take it," he says against the perfect skin between her breasts as he reaches back to unhook her bra. It's relatively plain, nothing lacy or sheer about it, an unsurprising shade of deep red that looks beautiful and dangerous against her milky skin. She slips it off her shoulders and tosses it aside, then rubs herself against his bare chest. Bruce can't seem to stay away from her beautiful mouth, so he dives in for another kiss as she reaches for his pants.
He barely feels her ease the button open, pull the zipper down, stealthy as ever, even when she doesn't need to be. Her crafty fingers dip down below the waistband of his underwear, and he makes it easy for her by lifting his hips, surging into her hand. There's no point in acting like he's not dying to be touched.
"Increased blood flow," he pants into her neck as he throbs in her grip, and she laughs as she teases her thumb across the head of his cock.
"Elevated body temperature," she shoots back, and skims her hand along the hot, aching length of him slowly, once, then twice.
He huffs out a laugh that turns into a groan as her grip changes to a snug circle of thumb and finger that she runs steadily up and down, winding him tighter and tighter with each stroke. "Good work, Agent Romanoff. Very thorough."
"I like to know what I'm dealing with," she says. Her other hand closes on the hair at the back of his neck and tightens, pulling his head back, exposing his throat. "Pain," she whispers, and closes her teeth on his jugular until his breath is hissing through his teeth. Her hand remains merciless on him, slow and unyielding, and at the top of every stroke, every time she slips it back down over the head, she bites him a little harder, her teeth like tiny points of fire on his neck. Just when he starts to think he can't take much more, she backs off, switching to soothing tongue and gentle fingers as he blinks up at the ceiling, heart pounding, on the verge of both coming and screaming.
It's a dangerous game, and they both know it, but he wouldn't play if he didn't think he could win. And Natasha wouldn't play if she thought she would lose. If they're careful, they can both get what they want from each other and walk away happy. Bruce needs this as much as she does, even if his reasons aren't the same.
Or maybe they are.
The muscles in her deadly thighs—Bruce has seen the footage—flex as she rolls to her feet next to the bed and tugs at his pants until he lifts his ass enough for them to slide free. He figures fair is fair, so he hooks two fingers over the front of her tiny red panties and tugs them down her legs. She's a natural redhead, he sees, trailing two fingers down and back until he finds bare skin. Her legs part a little more, just enough for him to feel she's wet and ready, before she moves away. That's not what she wants right now.
Natasha opens the drawer in the little table next to the bed without asking, but she's guessed right; he didn't waste any time stocking up once he figured out where this was headed. He even opened the box and tore a few free, just for the sake of expedience. The way the corner of her mouth ticks up when she looks in the drawer tells him this isn't lost on her.
She tears the wrapper open with her teeth as she crawls back onto the bed and kneels over him. He takes the condom from her with a hand that's shaking just a little bit, enough to make her tilt her head at him, lift a questioning eyebrow.
"Fear?" he croaks out, so turned on it hurts. His neck still stings, and he's having a hard time talking.
She meets his eyes, as cool as ever, even though she has to wonder if she's ten seconds from fucking Bruce Banner or facing down the Other Guy. She shakes her head. "No fear."
This is it, we're really going to do this, he thinks, newly aware of the fact that he's never had sex with anyone this dangerous before. The irony of that thought is not lost on him.
He rolls the condom on as fast as he can, distracted by the way she plays with his balls the whole time, tugging just a little too hard. Once he's got it on, she takes him in her hand and sinks down on him, eyes closed, teeth buried in her bottom lip.
This is one of his favorite parts, the first rush of snug heat enveloping him, and he closes his eyes and savors it for a moment. Only a moment though, because a view like this is not to be missed. When she starts to move, he gets with the program and grabs her glorious ass, not because he's under the illusion that he'll have any control, but because he's not passing up a chance to put his hands on it.
That turns out to be an accurate prediction. He mostly just hangs on while she does the work, fucks him hard and fast, fingers digging into his chest. "Don't you dare come until I’m done," she snarls at him, when he makes the mistake of lifting his hips up to meet her, fucking up into her a little too eagerly.
"I won't," he promises; he wouldn't dream of it. Being a practitioner of control has definite perks. He's in the zone now. He can wait. "I'm good."
"Are you?" Her hips don't stop moving as her hand closes around his throat and squeezes. "Shortness of breath," she says coolly, and the combination of her voice and her grip makes him buck beneath her. "Powerlessness." She tightens her fingers just enough to cut off his air. All he can do is make a strangled noise and let her ride him. "Are you still good, Bruce?" Her grip loosens a fraction, just enough for him to suck in a grateful breath.
"I can take it," he grits out. "Ride me. Fuck me. Come on my—"
And she does come, right then. Her eyes squeeze shut and her mouth falls open on a choked-off cry. She grinds down on him as the spasms shake through her, clutching him tightly by the cock and by the throat, and he's never felt more used. It's even better than he imagined.
When she's done coming, she barely pauses, just stops moving long enough to unlock her grip on his throat and balance herself with her hands on his shoulders as she comes up a little higher on her knees. Bruce happily takes several deep, wheezing breaths as she picks up again—shallow, hitching, up and down movements, just the head slipping in a little way and then almost out again.
"I’m not done with you," she says, with a small smile that would seem sweet if you didn't really know her all that well. And if her words didn't sound vaguely like a threat.
"I didn't think for a second you were," he manages. His voice is scratchy. He sees a shiver run through her when she hears it, nipples tightening to points, and he feels her clench around him in a tight pulse.
She grabs him by the wrist and pushes his hand down between her legs, where he can feel how slippery and swollen she is. She doesn't seem too sensitive, so he rubs his thumb in a small circle, adding pressure when she bears down on it. Her head falls forward until her hair is tickling his face, and she keeps teasing up and down, never moving enough for it to count for him, and he couldn't care less about it. When her thighs start to tremble, he rolls her clit between his thumb and finger, rougher than he's ever been with any woman, but she just urges him on with terse little commands for more and faster and harder. He does as he's told.
He reaches up with his free hand and pushes her hair back so he can see her, cheeks heated and red, forehead crinkled in a tiny frown as she works herself on him. "You're so beautiful, Natasha, you're amazing," he rasps out, and can tell the second the words leave his mouth they're a mistake, but he can't stop. "You're so--"
She grabs his head and kisses him, fucking his mouth with her tongue, and then pulls back enough to bite his lip instead of her own when she comes again, moaning low in her throat, shuddering around him. He uses his hands around her waist to steady her as she slows down, then finally stops moving.
"Excellent work, Dr. Banner," she says into his mouth, still breathless but with a familiar—though still rare—thread of humor in her voice. He can't help but smile as she licks lightly at his sore lip, relieved he's been forgiven for what he said.
"Thanks. Glad we had a chance to work together," he pants and rolls his hips a little, sliding in and out as much as he can. He'd like to come soon, if she'll let him. If she's done with him for now.
She lifts off him and strips the condom away in one quick motion, lips quirking when he hisses a little—he's painfully hard, and a little sensitive. She reaches between her own legs, eyes fluttering closed for a second as Bruce hears the soft, wet sounds of her fingers moving in and out of her body.
It looks like he's in for a show, that she's going to tease him for a while, so he's not sure if he's disappointed or relieved when instead she wraps her fingers, now slick and warm from her body, around his cock. It doesn't take long for relief to win out. He lets out a grateful moan as she jerks him off with short, quick strokes, not surprised at all that he's not allowed to come inside her.
She watches with glittering eyes and a smirking mouth as he strains up into her fist, giving up all pretense of patience now as she drives him quickly and ruthlessly over the edge. His head snaps back and he'd shout if his throat worked, but all he can do is clutch at the sheets with his hands as he comes hard, caught in her grip, powerless to make a sound, helpless and completely in her control.
She strokes him through it, until it's almost too much, and finally lets go when he twitches his hips, too far gone to express himself any more elaborately than that. Head reeling, dick still twitching against his stomach, he takes in big, greedy gulps of air through his burning throat and wonders if his thundering heart's going to explode. He can feel Natasha shifting against his legs, watching him. Neither of them says anything for a few minutes.
Finally, he works up the strength to lift his head. He half-expects to see the entire room trashed, based on how he feels, but Bruce himself is the only thing that's looking trashed. He's a wrung-out wreck of raised, red scratches, purple half-moon marks from her nails, the mess he's made all over his belly, and the faint sting of the bite mark on his throat. Natasha's breasts are flushed and her thighs are wet, and her hair is a little damp, curling against the sides of her face, but she otherwise looks just as smug and collected as ever. It's not a surprising outcome.
"Satisfied?" he asks unsteadily, though he already knows the answer. She's petting his thigh like he's a particularly obedient cat. It's the closest thing to affection she's displayed toward him so far.
Her answering smile is genuine, or at least the one she uses when she wants it to look genuine. She tightens her hand on his leg, a quick squeeze that's over almost before he can register it. "Very."
"Great. Good to hear," he says weakly. He absolutely will not make a Black Widow joke right now, no matter how tempting and accurate it may be.
She gives his thigh another squeeze and then reaches up to trail through the slick spots on his stomach. He nearly whimpers as she drags the tip of one wet finger down the underside of his cock, half-hard and almost unbearably sensitive.
"Refractory period," she sighs. Her mouth was made for pouting, but this is the first time he's ever seen her do anything remotely like it.
Bruce catches her hand in his, only a little shocked when she doesn't pull away. Now it's his turn to be smug. He grins at her and says, "Let me tell you a secret about gamma rays."