1.) A playfully angry reaction to one who hoodwinked you.
2.) A mouthy wannabe or wimp (noun)
3.) To be hoodwinked (buttsnacked, buttsnacking) (verb)
4.) To be anally raped (verb)
Damn it Kartman! You dirty rotten buttsnack! - Stan
Commonly, a piece of candy (i.e. Sour Patch Kids) that is inserted into one's anus; this often leads to outcry among people in the nearby vicinity, in which the undertaker of the buttsnack tries to force the candy into others' mouths, thus making them "buttsnacked."
Fafinal likes his butt snacks with salt.
Stuff in the butt you eat as a snack, such as poop.
You won't find buttsnacks in the grocery store near the Dunkaroos
when your cat or dog is going-to-town on his back-door or chocolate pocket.
dude, check that cat, he's havin' a butt snack! YUMMY!
Used as a noun, butt snack (also pronounced buttshhhnack) refers to a dumbass individual who fully believes in their own little deranged world that they are cool and/or funny.
Brian being the buttshhhnack that he is, thinks that he's funny.