The hair that goes from a man’s ankles to his waist, thus creating pants made out of hair. Only the men with big schlong’s have the best man pants. Not to be confused with a Man Onesie; which is hair that goes from a man’s ankles to his shoulders aka Chewbacca.
Girl 1: My boyfriend has the best pants!
Girl 2: OMG i know look at those Man Pants
Boy 1: Marc has the best Man Pants
Girl 1: I know, I'm gonna root him tonight!