A fork of Rural Dictionary
One or more buttocks and/or thighs with cactus spines in it, usually the result of an accident.
He crashed his mountain bike into a patch of cacti and came out with cactass. Because he could not pull them all out on his own, his buddies had to help.
The name of a mans ass when he is inbetween shaving and his ass is prickly hence cact-like.
"So how hairy is he?" "Lets just say if he stopped shaving he'd have a cactass" :O