goat brains Share definition Flag When a guy exposes only his nuts above the waistline of his pants. A guy says,"Bro, Have you ever seen goat brains before?" (while holding the exposed nuts in one hand, and pointing with the other" goat brains by Jason Spires April 19, 2004 0 0 Get merch Get the goat brains mug. Buy Now — $32.95 See more merch