fishy fanny Share definition Flag When a girls legs are open and a smll of fish suddenly creeps up on you, usually originating from the vaginal area. 'OH, FISH. Kadi, shut your legs.' 'You have a fishy fanny' fishy fanny by Jimmy Pee October 17, 2006 0 0 Get merch Get the fishy fanny mug. Buy Now — $32.95 See more merch