While doing a woman in the doggy style position, you place a pizza box on her back so you may enjoy some cheesy pizza during sexual intercourse. Two men may share the pizza as well while double teaming a woman in this position.
Greg and I were pizzaboxing some slut the other night and that fucker took 5 slices so I only got 3.
Doing a chick from behind while you have a box of pizza, can be any kind of pizza, and you put the box on her back and eat the pizza during hawt sexual intercourse.
Guy #1: "The other night I was totally pizzaboxing this chick, it was nuts. She was bent over and I was fucking her so hard she screamed 'OHHHH FUCK!!! YEAH!!!!!!' and the pizza box fell off her back."