It wasn't unusual for Tony to come to bed at a ridiculous hour, but Bruce generally liked to check on him around 1 A.M., just to make sure that "go to sleep" was at least on his to-do list. He'd long ago given up on getting Tony on a sane sleep schedule; you have to pick your battles, and he wasn't ready to die on the "eight hours a night" hill. He was making some vague motions towards the "at least three hours" hill, though.
When the workshop doors hissed open, Bruce was greeted by the sight of Tony hunched in front of some holographic displays, wearing the suit's glove on one hand and paying no attention at all to his visitor. His head moved slightly, eyes flickering from one screen to another, as his gloved hand flexed and relaxed at irregular intervals as he silently recited formulas and specs. He had dark circles under his eyes, and his hair was a mess. He'd stripped down to his tank top, the arc reactor's glow shining through the thin fabric, but he had a faint sheen of sweat on his shoulders.
"Hey," Bruce said, gently. Tony sometimes startled easily when he was caught up in his work like this. "How's it going down here?"
Tony didn't reply; his mouth kept working silently as he flicked a display over to another view. One gloved finger tapped against the frame of the stool, a sharp metallic sound that echoed through the room.
"Tony," Bruce said, a little louder.
Tony didn't jump or shudder, but he blinked twice, quickly, and turned to look at Bruce with unfocused eyes. "Huh? Oh, hi Bruce. What's going on?" He ran a hand through his hair, scratching vigorously. He was about due for a haircut, Bruce noted. "What time is it?" Tony said absently, turning back to a display and making a vague hand motion that changed the view again.
Bruce crossed the space between them and rested a hand on Tony's shoulder. "Quarter after one. Are you stuck on something?"
Tony leaned briefly into the touch, a tiny sigh escaping his lips. "Yeah," he said, weakly. "There's a...there's a thing. I can't find it."
Bruce's lips quirked up in a hint of a smile. "Care to be a little more specific?"
Tony sighed. "I can't." There was something helpless in his voice--a weakness, a sense of defeat. His shoulders drooped slightly. "There's just a--a sense of it. I'm missing something here."
Bruce peered at the display nearest him. It showed an assortment of power readings for the newest suit; repulsors, thrusters, unibeam, all laid out in a neat table. Bruce couldn't make much sense of it; as much as he tried to help Tony with his work, he couldn't wrap his head around the mechanical aspects like Tony could. He was a damn good physicist, but Tony was the engineer.
Bruce rubbed Tony's shoulder gently, squeezing just enough to make his presence known. "Maybe you should sleep on it," he suggested. "You came to bed pretty late last night."
Tony waved his gloved hand dismissively. "I'm fine," he said, his gravelly voice betraying his words, "I just need some coffee. I've got to figure this out before I put it away, or it'll take me hours to figure out where I was tomorrow."
Bruce looked closer at the displays, trying to make the connections. He picked out a couple of numbers that seemed off-balance. "What about this?" he asked, pointing. "The repulsor output seems a little de-synced from the arc reactor's cycle."
"No, that's not it," Tony said, frustration edging into his voice, "that's just an artifact of the, the..." he trailed off for a moment, then shook his head as if to clear it. "That's just from the adjustments I'm making to the transfer coils. It'll even out when I've got them finalized."
Bruce gave up on the displays and put his hands to work, kneading the muscles of Tony's shoulders and upper back. Tony's eyes fluttered shut for a moment while his thumbs dug into tight muscle, knotted from hours of tensely poring over engineering problems. It didn't last, though, and soon Tony was looking at the displays again, letting out soft sounds of appreciation, but slowly drifting away into his own thoughts.
"Is there anything I can do to help?" Bruce asked, more to interrupt Tony's train of thought than anything.
"You could get me a cup of coffee, maybe."
"I'm not getting you coffee, Tony. You need sleep, not caffeine."
"It's like you don't even know me," Tony muttered darkly. He jabbed a finger at a glowing model of the suit's left boot and twisted to open it up, exposing the panels and circuitry that made it up.
As much as Bruce wanted to drag Tony off to bed, he loved seeing him like this, fully caught in the throes of a puzzle, his brain engaged and his body thrumming with energy that would be released in a burst when he solved his problem and knew where to direct it. Bruce wished he could take Tony's mind apart like one of his holographic models, see all the neurons firing, watch all the connections being made. Understand Tony from the inside out.
But Tony wasn't getting anywhere, and leaving him alone now would only lead to him working until his body literally gave out from exhaustion. Even though passing out in the workshop would technically give him the rest his body needed, it would leave him in a foul mood tomorrow; what Tony really needed was a reset button. Bruce dragged one finger down the back of Tony's neck, over the ridge of each vertebra, and paused for a moment at the base of his neck, imagining a button there that he could press with a mechanical click. He gave a tiny press of his fingertip, then chuckled at himself and, before Tony could ask what he was laughing at, followed it with a swipe of his tongue.
Tony shuddered but didn't move away, and Bruce took it as an invitation to press small wet kisses in a line across Tony's shoulder. He kissed his way back up towards Tony's neck, stopping to nip at the line of the tendon there, and was rewarded by a noticeable increase in the speed of Tony's breathing.
"You're trying to distract me," Tony said, light irritation in his voice.
"I would never," Bruce said, sliding one hand to Tony's chin and tipping his head back for a kiss. Tony's objection was swallowed in the slow press of their mouths together, and Bruce slowly worked his tongue past Tony's lips before he could muster another one. He kissed slowly, deliberately. This wasn't just fun; it had a purpose.
"Come here," Bruce murmured against Tony's lips, stepping back slightly but maintaining as many points of contact as he could. He slowly spun Tony's chair towards him and urged him to stand with gentle strokes of his hands. Tony sighed, but it wasn't exasperation so much as surrender, and he stood, allowing Bruce to guide him until he was standing with his backside against a table and Bruce's hands on his hips.
If they were in the bedroom instead of Tony's workshop, Bruce would have spent a long moment admiring the lean lines and angles of Tony's body, committing to memory every dip and plane illuminated by the arc reactor's cool glow. He allowed himself a quick look, drinking in Tony's wild hair and hooded eyes, and the fluttering pulse in his neck, then he sank to his knees on the polished concrete floor. A hint of a groan escaped Tony's lips, and he grabbed the edge of the table behind him, causing a faint screech of metal on metal as his still-gloved hand clamped down.
"You are," Tony grumbled without any real anger, "and you would. You're trying to trick me into taking a break."
Bruce nipped gently at Tony's hardening cock through his jeans. "Is it working?" he asked with a tone of mild disinterest.
"Hhhngh," Tony said, and gripped the table harder. "You're so, so--"
Bruce smiled, his face pressed into Tony's crotch. He slid one hand up the back of Tony's thigh to cup his ass, squeezing with just enough pressure to press Tony harder against him. "I'm so what?"
"Nothing. You're so nothing. Just keep doing what you're doing," Tony sighed.
Bruce unfastened Tony's pants and worked them down just far enough to uncover the bulge in his boxer briefs. Bruce palmed him through the fabric, feeling the heat coming off him in waves, and was rewarded by a roll of Tony's hips against him. He breathed on Tony's cock through the fabric, the moist heat of his breath coming back to stifle him. "Bruce," Tony groaned, "stop teasing me and do something."
Normally, Bruce might have come back with a smartass remark, pointed out to Tony that he was doing something--it just wasn't what Tony wanted him to do. But Tony was not in any state to be teasing and playing, so Bruce took pity on him and freed his cock from the fabric briefs. Tony groaned at the firm touch of Bruce's fingers, and gasped audibly when Bruce licked a long stripe up his length.
"Oh god, Bruce," Tony breathed, "more, c'mon. Give me more."
Bruce dragged his tongue along the length of Tony's cock again, swirling around the head slowly, then took him into his mouth, slowly working Tony farther into his mouth with every stroke.
"Yeah, that's it, Bruce. That's what I need. Oh, fuck, like that. Yes." Tony hissed and gasped, babbling a constant stream of encouragement as Bruce sucked him and licked him. "Your mouth is so good, Bruce. So hot. Fuck."
Bruce hummed softly against Tony's skin on the upstroke, which made Tony's knees shake. Tony's hands slammed on the edge of the table, grabbing it with a white-knuckled grip as his legs shook and trembled beneath him. Bruce sped up, using the tip of his tongue to flick against the base of Tony's cock every time he took him in.
Tony was beautiful like this, gasping and cursing and disheveled, his legs barely supporting his weight and his eyes staring sightlessly into the distance. "Fuck, Bruce," he gasped, "that's good, so good. Just like that. I'm close, I'm so close. Your tongue...oh god, yes."
Bruce kept one hand on Tony's ass, guiding his hips in a slight thrusting motion, and used his other hand to cup Tony's balls, gently squeezing and pulling as he swirled his tongue around the head of Tony's cock. Tony let out a long groan, low and dirty, and took his ungloved hand off the edge of the table to rest in Bruce's hair. His fingers curled in Bruce's hair, but didn't pull, just held on, his hand following the motion of Bruce's head as he bobbed up and down on Tony's dick.
"Bruce," Tony whined in that desperate tone that told him he was about to come. Bruce sped up even more, his mouth making sloppy, wet sounds on Tony's dick, and Tony's hips came up off the table to thrust once, and then again and he was gone, coming hot and hard into Bruce's mouth while Bruce held on and moved through it.
Tony sagged bonelessly against the table, his shaking arms lowering him to the floor. He knelt in front of Bruce, his eyes glassy and his mouth slack. Bruce smiled at him and was rewarded with a half-grin in return. "You," Tony said, shaking his head, "are an asshole."
Bruce adjusted his glasses and smirked. "Sorry, I can't hear you over the sound of your knees shaking."
Tony laughed quietly, running his hand through his hair, and reached clumsily for Bruce, catching the edges of his shirt between fingers of flesh and metal. Bruce let himself be gathered up, encircled in Tony's arms like a child, and listened to the hammering of Tony's heart slow, his breaths become deeper.
Suddenly, Tony's posture stiffened, and his gloved hand hit the ground with a dull clang. "Oh my god, I'm an idiot! The stability thrusters' power isn't routed through the secondary controller board, so it's not--" He looked down at Bruce, apologetic. "I'm sorry, I shouldn't--I mean, do you want--"
"It's okay," Bruce said, smiling. "You can make it up to me later. Maybe after a good night's sleep."
"I'd love to," Tony murmured, palming Bruce's cock through his pants, the touch a promise. Then he was up and in his chair again, back straight and eyes bright as he made deft adjustments to his designs. Bruce watched him for a moment, warmth spreading in his chest. This was Tony at his best, building things, solving problems. This was what Bruce had fallen in love with. His cock ached pleasantly, still half-hard in his pants, as he watched.
Bruce pulled himself back to his feet, slowly--as much as he hated to admit it, he was starting to get too old for sex romps on concrete floors--and watched Tony for a minute longer before planting a kiss on the top of Tony's head and leaving. Tony would be along soon--he would ride that wave of endorphins for a while, get some work done, and leave himself some notes that a less sleep-addled Tony would be able to make sense of.
Then maybe after breakfast, they could work on one of Bruce's problems. It would only be fair.