Similar to a prenup, where a contract is made before the sexual encounter to ensure zero emotional liability, zero stalking, zero kiss-and-tell and zero phone calls the morning after, or alternatively STD-treatment bill and abortion bill insurance.
Dips: I don't want to be any girl's first or last. That's just too much baggage.
Bhai: You're just scared! I'll tell you what, sign a prefuck. That way you can be sure she won't stalk you afterwards.
You and a significant other arrange to meet before a date and engage in vigorous sex before you both get too drunk or something. Also is a great way to break the ice.
Guy 1 - Dude I am getting bombed at the bars tonight.
Guy 2 - Aren't you going with Jordan, what if you get whiskey dick?
Guy 1 - It's okay, we are going to Prefuck at her place.