the ass hole
she loves it up the butt, gonna get me some round brown tonight
a fart, toot, poot, poof, puff, fluff or whatever else one may call the secretion of gas from the buttox
other examples: anal acoustics, cabbage captivator, talking pants, Victoria Secret's worst nightmare, fumigation
Bob: (round browns) "Aaw that smells! Gary, did you round brown us?"
Gary: "What? HEAVENS NO!"