Someone who overestimates himself, believing himself to be something that he is not.
Origin: A friend of mine thinks he can "sing like a lark" but he sounds like ass.
Jonny is such a Buttlark, he cries like a baby, but he thinks he is really tough.
the white stuff that comes out of a rectum after prolonged anal sex, usually when the anal cavity is stretched and unable to close.
Man 1: Dude, there was a cheerleader in the guys locker room
Man 2: Wait what?
Man 1: Yea, she took the whole football team up the ass, she blew out and everything Man 2: *shudders* Ugh.. thanks for the mental image of buttlard man