The nanite armour had never been intended for sex.

He wanted that on the record.

Tony flicked the small demonstration of nanites into the shape of a fist. He used them to pick a bolt up, throw it in the air and catch it. James was pressed against him, arms around his middle, chin hooked over Tony’s shoulder to watch. Tony was reluctant to break the hold, so when he called the nanites over he only covered his hand and forearm.

The nanites danced against his palm in a wave, then Tony turned them into a perfect cube, a repulsor, a flower.

James ducked his head into Tony’s neck when he offered it. Alien invasions, heavy artillery, facing down a senate committee; none of these things fazed James. A flower from his boyfriend and suddenly he was shy.

“No, thank you.” James said firmly.

Tony let the flower go. He flared the nanites out a little, showing off. The stem thickened, split, danced for a minute, spinning in Tony’s palm like the coordinated limbs of an octopus—

The interest behind him changed suddenly.

“What have you got there?” The tone was distinctly different, Bucky now, talking silky and low, his lips dragging over the skin where Tony’s shoulder met his neck. He pressed more firmly into Tony, reaching for the spinning tentacles with his metal arm.

“That was sudden.” Tony let the metal appendages grow, eliminating the gap between Bucky’s hand and the nanites. He made them as smooth as possible. They should almost feel like liquid.

“It could have scared him.” Bucky pressed his hips more solidly into Tony’s. Hello, Tony was the only one growing something. “Think he might just’a known how much I’d want to see. How strong are they?”

Bucky tried to pull the arm back, Tony wrapped one nanite tentacle around his wrist thick and heavy and held it in place. The other ones flitted in and out, petting and caressing, making a show out of it.