when a high school student puts a paper bag over their head in order to remain anonymous and then proceeds to run into a random classroom, pull their pants off, and point their ass at the whole class and subsequently the teacher, shortly before making their escape.
Did you hear? Mr Ahl's 6th period got moon gooned, no one has claimed responsibility but multiple witnesses say the culprit had a smokin jo's bbq tshirt on. (moongooned being the past tense of moongooning)
The act of gooning under the the open dark sky, exposing yourself to the moon. Typically done with the natives of the region with elk skulls. Some cultures claim reaching for a polices gun whilst moongooning will enlighten your soul to a Valhalla like state.
Cop: Sir have you been unauthorized moongooning tonight?