sex gerbil Share definition Flag is when you place a tollet paper roll in your ass and you let a gerbil craw up you ass and then jerk off over your dog son let me borrow your gerbil to stuff up my ass while i jack off on our dog sex gerbil by dick fur February 22, 2005 0 0 Get merch Get the sex gerbil mug. Buy Now — $32.95 See more merch