When you cover your dick with a the first thing you see and end up getting a boner.
Lady 1: Hey baby! My and my friends are back!
Guy: Oh! Hey babe!
Lady 1: Where are your clothes Jeff?
Lady 2: Why is the only thing you're wearing is a hat in you junk?
Guy:Well, I just happened to be rosterbating...
Lady 1: And what is that bulge?
Lady 3: Looks like Jeff got a Bonny Johnny.