An act performed usually by two female strippers, with an observer. The observer lays on the floor, then the first stripper lays face up on the observers chest so that his head is pretty much between her legs. The 2nd stripper then lays face down 69 style on top and proceeds to perform cunnilingus on the first stripper while the observer gets an up-close view.
Brad must have loved his bachelor party, those strippers gave him a human mattress
someone who sleeps around
a prostitute is a human mattress