After trying to search for it myself, I'm looking for a Tony/Bucky/Steve fic. Bucky and Steve are already in a relationship. They are trying to woo Tony. Tony thinks they are playing around so it hurts because he has feelings for both of them. Clint comes in, and to prove a point, tries to kiss Tony while sitting on his lap so Steve and Bucky get jealous. Then Clint leaves with Natasha. Happy ending ensues.