Flumper thumper Share definition Flag Someone who has 2 penises in their butt at one time that result in anal juices. Lets go give that girl a flumper thumper. Flumper thumper by Mak2356774 February 21, 2018 0 0 Get merch Get the Flumper thumper mug. Buy Now — $32.95 See more merch