fwapa fwapa Share definition Flag orientation- Spanish. The sound of the male sex organs slapping the side of his leg when: jumping, running, or making his friends laugh. Michael did the Fwapa Fwapa today when he was running, i couldn't stop laughing. fwapa fwapa by datnjdvl13 June 7, 2009 0 0 Get merch Get the fwapa fwapa mug. Buy Now — $32.95 See more merch