Banana Slammin' Share definition Flag The action of striking a penis against another penis or penises. "My gay brother is in his bedroom with another dude doing some 'Banana Slammin'" Banana Slammin' by peyotesunrise December 16, 2011 0 0 Get merch Get the Banana Slammin' mug. Buy Now — $32.95 See more merch