When someone places their lips in the recently used/dirty butt crack of someone else, makes the "Brrrrr" sound of a motorboat, and shakes their head back and forth very quickly.

When a woman happens upon her man having a wank while lying on his back, she disrobes and straddles him in a similar fashion to the reverse cowgirl. However, unlike the sexual position, the woman nestles her man's ball sack between her butt cheeks and proceeds to fart on them as many times as possible, creating a wonderful vibration for him and audibly resembling the engine of a motorboat.

When smoking a cigarett, you exhale on a girl's chest, while she is giving you a motor boat! After you're done, you tell her..."Bitch you got a broken motor!"

The act where one presses face against a guys genitals and rocking one's head side to side between the balls very rapidly while making a vigorous, lip-vibrating "brrr" sound.

The act of motorboating a woman's breats and/or vagina, imediately after releasing your seed onto them/it.

the male grabs his penis and the woman grabs his arm and works it for him or two guys each grab there dicks with one hand then there free hand works the other guys arms

When you squeeze a woman’s butt cheeks together and she farts in your face