A term used when you are laughing insanely hard. Similar to laughing your ass off, you are busting a nut, because you are laughing so hard at a persons joke.
Jeff: "Damn, look at her camel toe gobble up those tights!! Hahahahah"
Carlos: "Oh my god! I am busting a nut laughing right now!!"
The placement of one's face, specifically the mouth, into the area between a woman's buttocks, followed by a rapid shaking of the face in a side-to-side motion accompanied by expelling a large amount of air. The resulting sound that is created sounds similar to an outboard boat motor.
Frank, looking for a change, and because his chick has a sweetbadonkadonk, engaged in saddle boating much to his girlfriend's delight.