Where a large bellied individual raises his or her stomach and allows it to drop upon his or her sexual partner in a way that creates a *smack* sound. This is an act performed for sexual pleasure.
Man, my back is killing me from a night of gut flopping with your mom.
by Barringo November 10, 2007
An unusual fetish act where the submissive bottom is hit by the obese dominant's massive belly. The large gut is lifted up with both hands and flopped onto the other party.
He was on all fours and she was gutflopping his back.
by altapr March 16, 2008