After being thawed, Steve's adrift in the 21st century. There's nothing for him here, just the endless cycle of pre-packaged food, pointless training exercises, and long hours at the gym. But when he takes on a new project, it leads him to a new friend - one who might open up all kinds of new doors, new feelings, new experiences. Or might just break his heart.
One slip of the thumb means that Tony just texted a picture of his dick to Captain America instead of his casual hookup. Which is just as well because the guy hates him anyways.
It's certainly the weirdest way he's ever managed to break the ice.