The morning before they head out to watch the Fourth of July parade – and be watched, since after all they’re America’s Heroes or whatever the title is this week – Tony gives Bruce a shirt and begs him to wear it to the parade. It’s black, with little white specks on it, and when pressed, Tony admits that it’s an astronomically accurate (mostly, since it’s a shirt) map of the stars as seen from Stark Tower in midsummer. Bruce is baffled, but gives in to Tony’s begging puppy eyes and wears the dratted thing to the parade. It’s very comfortable, actually.
The uncomfortable bit is the way Tony looks over every so often, usually after Bruce has waved to a small child who is pointing and cheering at him, and giggles. There is something uniquely worrying about Tony Stark giggling.
When they get back to Stark Tower, it’s actually Natasha who asks what everyone is thinking: “Stark, what the hell was so goddamn funny?”
Tony cracks up completely, and through his giggles he manages to gasp out, “Oh, say, does that star-spangled Banner yet wave?”
…He gets ten seconds head-start while the rest of the team recovers, and then they spend the rest of the day finding new and creative ways to torture him, because wow that was awful.
…Bruce keeps the shirt.