Grandpa Shark Share definition Flag To fist someone in the vagina and ass at the same time. It looks like a shark's mouth. Girl 1: He grandpa sharked me! Girl 2: Ohh, I bet you loved it! Grandpa Shark by Blahblahblahblah123:DDDD July 29, 2010 0 0 Get merch Get the Grandpa Shark mug. Buy Now — $32.95 See more merch