The euthanasic term for "silly ass".
It's used for referring to someone who is extremely silly or just plain ridiculous.
It could also be used to poke fun and tease someone as it assumes that they are ignorant and immature/childish.
When someone sticks their finger down the crack of their butt and then swipes it across someones nose. Same technique as a wet willy. Pronounced But-twilly.
I gave Ty a buttwilly today after working out, I bet he can still smell it!
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).