This is when a guy subconsciously or consciously sticks out his chest to reveal that he is proud to have just accomplished a task he feels only a man could do. Or he feels good he was able to help the woman that really seems like she never needs anything.
woman: I dont know whats wrong I just cant get this to work. I have tried everything.
man: let me see ( has no real idea but tries something and it works)
woman: oh you did it! wow why didnt I see that?
Guy smiles proudly and puffs out his chest in quick almost involuntary instance and says "no problem"