Also spelled wassin' - the act of wiping spit, snot, or any other type of bodily exriment onto a window.
The game of wassin', played like "ding dong ditching" where one goes up to a door, spits on the door (mucus, feces), rings the bell and runs away. This game can be played with a group where multiple people spit on multiple windows before the doorbell is rung.
Hell yeah, i was wassing on all of her windows. She'll have a fun time cleaning that up.