a sexual activity in which a person chokes their partner until their blue, and then craps on their head.
"i gave Ellie Mae a blue bonnet last night."
A synonym of the term "Butterface," this term can be used more covertly to express your opinion of a girl's appearance without arousing her suspicion. Inspired by the logo on the famous brand of margarine.
Q: "Hey, what's that party looking like?"
A: "Eh, just a bunch of Blue Bonnets hanging out."