Wiktionary
vb. (context intransitive idiomatic English) to cease to be involved in a concern
Wikipedia
"Butt Out" is episode 109 of the Comedy Central series South Park. It originally aired on December 3, 2003.
The episode pokes fun at the formulaic storyline of some South Park episodes (including the movie), which start with the boys getting themselves in trouble and inciting a controversy between the townsfolk and a national interest group (or a major catastrophe) while trying to avoid punishments, subsequently learning a lesson from this conflict.
Usage examples of "butt out".
And if you don't stop that and get your butt out of bed, your breakfast will get cold.
When the litterbug flicked a cigar butt out the window, Twilly didn't bother to stop.
Fallon finished the cigarette and crushed the butt out on the sole of his shoe.
If you were anybody elses brother, Id kick your tight butt out the door right now.
Training covered this situation explicitly: her duty was to report her findings to local authority, turn over anything she had, be available for interviewing should they deem it necessary, then butt out, be a private citizen.