An act of oral sex that requires the woman to lay on her stomach and prop her booty up. Upon doing so, several drops of water must be poured onto her booty. As the water trickles down the middle and down to her vagina, it must then promptly be licked up.
Hey man, last night my girl went crazy when I did the vagina waterfall with her.
by TheMadRussian April 21, 2015