when a female and male rub together in the nude and a suction occurs, causing a farting noise.
"Dude, last night, i was getting all hot and heavy with that girl sophie and her boobs totally farted"
"no way, gross"
"naw, man. the boob fart was hot"
When a girls boobs rub together and make a fart noise
"Hey Darlene, I just heard your boob fart