1) A burning sensation of the anus regardless of cause, which can be many; diarrhea from spicy foods, anal sex, etc...
2) A person who is elevated in loathesomeness to the next level beyond being a pain in the ass such that now is more of a burning rectal sensation rather than merely a simple pain.
When I had the squirts last night it was a real buttpepper.
Sally had a buttpepper and didn't shit right for a week after the football game party.
Ruler of Lake Titicaca. Rumored to have a bunghole that gets very angry if it does not receive toilet paper. Cornholio the Great is often seen walking around with his shirt over his head and his hands in the air, chanting songs about his power, and his bunghole.
"I am Cornholio! You do not want to face the wrath of my bunghole, for I need TP!"
Butthead: Shut up, Beavis! (uh huh huh huh)
Beavis: Um, okay. (heh heh heh heh).