As far as Bucky was concerned, there were two things his metal limb was good for; murdering people, and being used as an excuse to spend time with Tony Stark. Considering he was all out of people to murder, he was mostly concerned about the second part.

Since Steve had found him and dragged him back to the Avengers Compound, his childhood friend had been insistent on him exercising his free will. The problem was there weren't many things he really wanted to do. In fact, after having a long bath, a good night's sleep, and a home-cooked meal, Bucky had really reached the bottom of his list. Because the one thing he really wanted was something he should not peruse - Tony Stark.

Tony Stark, whose parents he's murdered with his own hands. Tony Stark, who'd been told this by Steve long ago, and still helped look for him. Tony Stark, who let him stay in the compound. Tony Stark, who was so smart and kind and wonderful and...

And it didn't matter if Bucky had feelings for him. Tony was in love with Pepper anyway, Bucky could never compete with her, he didn't even have red hair! And she had the advantage of not having killed Tony's parents in the name of Hydra, that had to be a pretty big plus. Tony wasn't even gay.

Bucky had always been gay. He'd known it from a young age, when every boy he knew became interested in chasing skirts and all he wanted to do was hold them down and 'wrestle.' But instead he dated dozens of girls, each one pretty and nice, but all interchangeable. Had he returned from war, he would have married one of them; which would have been unfair, but in those days there was little else a man could do. Now he could marry a man, divorce him, and then marry him again. The future was amazing in that way.

But he couldn't have Tony, and that was okay, he could resist. Well, he could resist most of the time. There weren't exactly a lot of situations where he and Tony could just hang out together, so he favoured creating these situations himself. Usually in the form of breaking his metal arm. It was a surprisingly easy thing to do, if you knew what you were doing. Bucky knew his arm well enough to stick a screwdriver in just the right place to mess with the mechanics of it, then he would go running to Tony, claiming he had absolutely no idea how it happened.

Tony was a gifted engineer, and could fix the actual problem in a matter of minutes, but it always involved pulling Bucky's arm apart, and with all the plates and screws, this could take up to an hour. Yet he never complained, and he never accused Bucky of being the source of the breakage, he just fixed it, idly promising to make Bucky a newer, better arm, yet that never happened.

Until it did. After months of Bucky coming to Tony every couple of days, the genius had finally got fed up, and had constructed a new arm, with all the durability Stark technology had to offer. It was early evening when Bucky made his way to Tony's lap, holding his broken metal arm theatrically, hoping to get another how with Tony, when he was greeted by him holding the new contraption, looking oddly proud.

"Here, I made you a new one," he said with a grin, clearly very pleased with himself, "it's much better; unbreakable, more flexibility, smoother use, it's even easier to use, try it on!"

Bucky was shocked, how could he say no? His malfunctioning arm was the only thing that kept him even remotely connected to Tony, and if he started breaking this new one, Tony would find out, he'd figure everything out.

"Uh, thank you," he said slowly, trying to seem happier than he was. He managed a small smile, and detached his current arm, ready for to put the new one in its place.

"I've been looking at your joint socket," Tony said, walking over to him and measuring it up, "it was easy enough to recreate. Sorry it took so long, I've been busy."

"You didn't need to do this," Bucky offered, "not for me. You're always so busy..."

"It's fine, what are friends for?" Tony smiled, clicking the new arm into place.

Bucky felt the weight of it pull at his shoulder, but unlike his previous one it wasn't uncomfortably heavy, it was light and painless; he might even be able to wear it while sleeping. In place of the red star that marked his other one there was an Avengers A.

"Friends?" Bucky breathed looking at Tony hopefully.

"Yeah," Tony replied, like it was a promise, "friends."

The smile Tony gave him immediately eased any doubts in his mind, and he couldn't help but believe Tony really did think of them as friends, and friends could hang out without a reason, right? So, he didn't need to keep breaking his arm, and he could enjoy his new one.

The next few days were a lot easier on Bucky, this was mainly due to his brand-new arm. Daily tasks like making coffee used to be frustrating, his old arm wasn't exactly built for finesse, and he regularly found himself dropping or crushing bowls and mugs. But his new arm was gentler, easier to manoeuvre around handles, and touching the TV remote. It was unlikely to be as good in battle, unless Tony ended up adding a blaster to it, like he promised, but Bucky didn't really want to battle anyone ever again, so that wasn't really a problem.

And he'd also found the confidence to start approaching Tony without a reason. Most of the time he didn't say anything, he just watched Tony work. Occasionally he would ask a question about the mechanics of Tony's suits, and Tony would answer him happily before returning to whatever he was doing. He was always down in his lab, a place that most on the team were strictly forbidden from entering, yet Bucky got a pass because of his arm breakages, and if Tony didn't kick him out he wasn't going anywhere.

It wasn't really the place he'd expect to find Tony in a... compromising position. But that's what happened. He'd just finished eating dinner with Steve and excused himself to wander into Tony's lab, as he's been curiously watching Tony toy with his new experiment all day.

He heard soft moans resounding throughout the large lab, and for a terrifying moment he feared Tony had been hurt.

As it turns out, it was quite the opposite... Tony was on his knees, naked from the waist town, wearing nothing but a T-shirt, legs spread wide as he stroked his cock repeatedly. Bucky gasped quietly, Tony hadn't seen him yet, and it was probably bed to keep it that way.

Tony moaned a little louder, and Bucky watched as his deft hands worked their way up and down his own shaft. Bucky soon realised that he was also bouncing on something, a dildo perhaps? He took a step forward to get a closer look, and in that moment, Tony looked over to him.

"Bucky!" he exclaimed, stopping completely, look of horror spreading over his face.

"Sorry, I'm so sorry," the words spilled from Bucky's mouth as he held his hands out apologetically, "I just wanted to see-" he noticed a familiar metal glint flicker from underneath Tony's legs, "... is that my - my arm?"

Tony blushed furiously, tucking his face into his hands.

Bucky moved closer, close enough to see that it was certainly his arm, his old one, that Stark had been using to... fuck himself! Bucky grinned as he got an eyeful of three cold metal fingers inside of Tony, that only moments ago the man had been moving to work himself open.

"I'm sorry Bucky," Tony said, pulling the arm out of himself, "I just - I don't even know what to say."

"I put that arm back in my room?" Bucky questioned.

"Yeah, you did," Tony confessed, "I went and found it."

He still hadn't moved from his position on the floor, his erection still stood strong between his legs, and Bucky wondered if he like the idea of being caught.

"You could have asked me," Bucky said with a sly smile.

"And say what, 'hey I have a tech kink, can I please use your prosthetic to fuck myself?'" Tony grumbled.

"No Tony, you could have asked me," Bucky emphasised.

Tony look confused for a moment, then realisation dawned on him, "Oh," he said breathlessly, "well Mr Barnes, will you use your prosthetic to fuck me? and your dick too, actually, while your here, a dick would be great."

Bucky laughed, "Gladly," he winked, "it'll be nice to put this new arm to good use." Bucky pulled Tony up from the floor, planting a soft kiss on his lips, "Wanna move this to your bedroom?"

"Too far," Tony protested, "we can stay here, I have a mattress in the lab."

"You have a mattress in the lab?"

"Bedroom's too far," Tony repeated with a groan, and Bucky remembered that Tony was probably feeling desperate right now.

With very little effort he lifted Tony into his arms and kissed him again. Tony hummed happily, wrapping his arms and legs around Bucky, like a particularly good looking octopus. He broke the kiss briefly and commanded, "FRIDAY, will you pull down my bed?" The AI didn't respond, but seconds later a part of the wall detached, slowly lowering down an extravagant bed. Bucky was curious to watch, but he was interrupted by Tony kissing him again forcefully; so, he opted to carry the genius over to it.

"Oh fuck, Bucky," Tony breathed, tugging at his shirt impatiently, "I need you. Get out of these fucking clothes."

Ordinarily Bucky felt quite self-conscious about having his shirt off, he was always acutely aware of people staring at the joining between his skin and arm, he hated them staring. But Tony has seen him shirtless plenty, Tony regularly had an up close and personal look at his metal prosthetic; and not only was he not disgusted, but he liked it, it was a large part of the reason he was attracted to him. So, Bucky had no qualms about getting undressed with Tony. Arm aside, Bucky knew his body was impressive.

After ridding himself of his own shirt, he started to lift Tony's. Bucky felt him grow cold, even though Tony kept kissing his, he was suddenly slow and unsure.

"Is something wrong?" Bucky asked.

Tony paused, "This is a kinda weird request, but do you mind if I leave my shirt on?" Tony had his own insecurities too, there were deep scars in the centre of his chest, leftover remnants of having the arc reactor removed.

Bucky nodded immediately, "Of course," he grinned flirtily, trying to bring the mood back, "I hardly need that to fuck you, now do I?"

Tony's face lifted with relief, and he placed a kiss on Bucky's jaw, "You better not be making promises you can't keep," he teased, "I'd bet money it's been a real long time since your last fuck, and you better not finish in 30 seconds."

"I have amazing self-restraint," Bucky countered, "it's you I'm worried about - you're not as young as you used to be."

"That's a laugh. How old are you? A hundred?"

"Okay fine. We're both old, can I kiss you?" Bucky asked leaning in.

Tony placed a finger on his lips, "You can, but you gotta take those pants off first."

Bucky was all too happy to comply. While he was generally good at ignoring such things, his erection had been pushing against his jeans uncomfortable for several minutes. Tony watched in tender anticipation as Bucky unzipped himself, and pulled out his heavy cock. It was both longer and thicker than Tony's. Tony stared, practically watering at the mouth; the way his big brown eyes widened prompted Bucky's cock to strain harder.

"You should lay back," Bucky suggested softly. Tony did as he was told. "Hey FRIDAY? Some lube would be great," Bucky directed at the AI. Again, the computer was silent, but a mechanical claw descended from the ceiling and placed a small bottle of lube in Bucky's hand.

Bucky spread Tony's thighs with both hands, one cool clean metal, the other warm and calloused. "Oh fuck," Tony whimpered softly."

Bucky chuckled, squeezing the contents of the bottle onto his metal fingers. Slowly he entered with one, Tony cringed, but Bucky could tell it was only a slight discomfort from the cold, and not any kind of pain. Tony was still loose from when he'd been fucking himself, but the way he moaned prompted Bucky to open him up further.

"Oh god! Fuck, fuck, fuck-" Tony cried as Bucky added another finger. Tony just loved the feeling of the smooth metal inside of him, just knowing that Bucky could do this forever without his arm ever tiring was incredibly hot.

Bucky finger-fucked him with slow, deliberate motions. Every new movement would draw another delicious sound from Tony, and his new arm was so much better at feeling and judging where things were, Bucky could prod Tony's prostate with ease.

"More!" Tony begged, "Please, Bucky..."

Bucky complied and added a third finger, he felt Tony stretch this time and wondered if he'd pushed in too hard. Tony immediately reassured him, however, by moaning deeply and rocking back onto his metallic fingers. Bucky's cock throbbed insistently, painfully reminding it that it was there, but Bucky was far more interested in Tony's, which was near-straining against his stomach.

"You're not touching yourself?" Bucky observed.

Tony huffed in exasperation, "I don't want to come yet, moron," he choked out, trying not to moan.

Bucky nodded, thrusting his fingers once more deep inside of Tony, before taking them out and caressing Tony's thighs with both hands.

"Fuck me, Bucky," Tony demanded. Bucky wanted to chastise him, but his cock throbbed again and he decided against it.

He found the lube again, quickly spreading it over his cock, and lining up with Tony's gorgeous ass. Despite all the effort he put into stretching him, Tony still fit snug around him as he slowly slid in. Bucky gasped quietly, pleasure spiking through his body, "Tony he whimpered, leaning down to kiss him hungrily, "fuck," he cried, thrusting into him.

Tony moved to meet his thrusts, trying to keep as much on Bucky in him as he could. "Holy fucking shit," he whined, "fuck! Harder!"

Bucky complied, roughly grabbing Tony around the middle, and sped up, setting a sharp rhythm. He couldn't remember the last time he'd done this, he certainly hadn't done it since he left Hydra, but as far as he was aware he hadn't had sex since the 40's. For that reason, he found himself much closer to the edge than he ought to have been, the compulsion to clutch Tony and come inside of him was strong. Instead he gritted his teeth and forced himself to keep going, he doubted Tony was far off anyway, and he could wait.

Tony whimpered helplessly, the faster Bucky was the more he could get lost in the pleasure. Bucky was gripping him in a way that was likely to leave bruises, he was using his super strength, but Tony wouldn't dare ask him to stop, he liked it.

"I'm gonna-" Tony choked out, legs shuddering as he felt the knot deep inside of him unravel and his balls clenched with relief. Bucky continued to fuck him, watching with fascination as Tony spilled onto his own stomach.

With a growl, Bucky gripped him tight, pulling him into a kiss and giving one final thrust before coming deep inside him.

Tony relaxed into the bed, feeling Bucky soften inside him, he was completely exhausted, though his super soldier didn't seem to have exerted any energy at all, he was just grinning like an idiot. They lay like that for several minutes, Bucky apparently not minding being soft inside him, and Tony didn't really mind either.

"That was pleasant," Bucky observed eventually.

Tony smirked, "Well... Yeah."

"You want to keep my arm?"

"I think I'd rather keep you," Tony said with a kiss.