squirrel brains Share definition Flag The appearance of a male's scrotum when he squeezes his testicles so that the skin is taught. "Hey, lets get a picture of your squirrel brains on Blake's passed-out face" squirrel brains by Rubbaneck November 16, 2004 0 0 Get merch Get the squirrel brains mug. Buy Now — $32.95 See more merch