When you are excessively sweaty (preferrably upon finishing at the gym), you take your hand and use it to accumulate the sweat from your testicles and wipe your hand on a friend's face.
Guy 1: "Dude, that was an awesome work out!"
Guy 2: "Man you're so sweaty though"
*Guy 1 performs duck soup*
Guy 1: "What the fuck dude, duck soup is so nasty!"