As told to me by my coworker Adrienne because we didn't spend that kind of money to go to a concert:
She was standing in line to use the portapotty, when the woman inside the portapotty yells out "How do you flush this thing?" To which Adrienne felt the need to respond "Um, you don't."
"What is this thing on the wall?" the woman yelled. "The urinal?" responded Adrienne.
"Why is there a sponge in it" was the next query. "To keep it from splashing" yelled Adrienne as she decided she might not have to pee so badly afterall.