The act of a male slightly spreading his legs and swinging the genitals back and forth causing them to hit the front and back of the pelvis, creating a "Flop" sound. Can also be performed during the dance of the Hula Floppy. Sounding simple in theory, most mens sachels' are to sensitive and not large enough to withstand the force of swinging.
A:What's that sound?
B:Oh thats just Floppy; The Segraves Floppy man.
A:Holy crap..I could totally do that!
B:Bet you can't fool.
A:<attempts floppy> Dude, you're right...That just hurts my balls to much.