Okay latest unhinged winteragent idea (pre-relationship):
What if Bucky's arm is acting up and the bolts are like "you need to go to Wakanda to get Shuri to fix it" and he's like "nah I think it's something small we can fix it here"
Cue the bolts huddled around Bucky with the panels open to the mechanisms at the backside of his shoulder and Shuri on FaceTime trying to walk them through replacing a damaged part.
They're struggling and their banter with each other isn't helping, but it's still a quicker fix than going all the way to Wakanda, and Bucky's dealt with worse anyway, so he's trying to be patient.
At some point when Yelena fails to get to the right tiny screw deep in his arm, Walker goes, "Here, let me give it a try."
"You seriously think you stand a better chance with those big man hands of yours?" Yelena shoots back.
"I used to fix my car all the time, I'm good at mechanics," John insists.
He steps right up behind Bucky, leaning in close enough to inspect the situation that Bucky can feel his breath on his neck, can swear he can feel the body heat of his chest nearly pressing his back.
He places one hand on Bucky's nape to hold him steady, and then his other hand is slipping into the mechanisms, fingertips running over tiny gears and cogs that normally never get touched by anything, anyone, and Bucky can feel it all. Walker is surprisingly gentle, his touch for inspection more like a caress, and for some reason it hits him that Walker is basically inside him, and--
He jerks forward, out of reach. "Nope, someone else's gotta do it."
"What? What'd I do wrong? I'd barely even touched anything," John says.
"You're like, breathing all up on me, it's freaking me out," Bucky complains, shivering from the absence of his warmth as the girls chuckled and probably took it instead as a shiver of disgust.
"And with your meaty hands you were probably touching more than you realize," Yelena says, and Bucky really wishes she'd stop pointing out his hands.
John scoffs, clearly annoyed that he'd barely even been given a chance, but he doesn't protest any further.
"Honestly, just let me do it. I can use my powers anyway," Ava said, shoving the flashlight and phone to Yelena.
John sits in front of Bucky, shrugging. "I could have done it."
Bucky just hopes his blush isn't evident.
