Ok but… Tony doing something incredibly reckless on a mission, and yeah it works but he breaks his arm, badly. Once the initial worried yelling at him for being an idiot is over, the team asks if they can sign it. Clint writes something obscene on the the bottom where Tony can’t see, and Phil smacks him for it. Natasha signs it and draws a terrifyingly graphic picture of her breaking his arm if he ever does something like that manoeuvre again. Bruce just sighs and writes his name in a green pen, to shut Tony up. Thor draws a little Mjolnir, and says that Tony’s inability to lift the hammer is what is rendering his arm immobile. Bucky doesn’t sign it-he just smirks in the background. Tony is suspicious. Finally it’s steves turn, and he gets his paints and brushes out and tells Tony to close his eyes. Tony does, not sure what to expect, and when he’s told to open them steve has painted his arm metallic silver, with drawn on grooves and bolts, and a red star on the top. Bucky is pissing himself in the corner, as steve proudly announces he now has a matching set of boyfriends. He has to sleep on the couch that night, but it’s so worth it.