When you're on the toilet taking a shit, and you pick up that huge cup-shaped thing filled with water, wash your ass with it, and the water floods over the toilet, infested with ass juice.
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.