It is the act of copulating, sex, bumping ugly's, or something along the lines of that.
mike: Hey danica, lets go to my house, and get some free pizza!
danica: FREE PIZZA! ALRIGHT! I love pizza!
mike: Your a fuckin' dip! (dip shit) nvm I guess im just going to have to teabag you.
me and my girlfriend are constantly having free pizza.
The act of having sex with someone you find unattractive just for the sake of getting laid.
"You had sex with that?!"
"Um...yeah. You never pass up free pizza!"