When two people are performing oral on each other's asshole. Just like 69 but with the ass instead. The act of two people tongue-punching the other'sfart-box.
Bro, me and Jane had a Fart Boxing match last night. It lasted 3 rounds before she got KO'd.
By Babbie
Fart Boxing
An event where two people trade offcracking farts until one is either out of farts or can no longer stand the smell of his opponents flatus.
Wayne was defeated in an early morningfart boxing match when he admittedly could not take the smell of Joe's bout winning spinach fart.
By Eryn
Fart Box
a derogatory term for a 'pimped up ride' or 'chav mobile.' shitty old cars with massive exhausts cars which will make loud fart like sounds. Therefore it is siple logic that if the exauhst souns like fart then the car is an ass/big pile of shit
evry1 climb into ur fart boxes and close ur ears we are off for a cruise