So you're at least 21 years old and don't know how to play paper-rock-scissors?

That's ok, we'll help you out:

Basically, both players hold out their fists.
You shake your fists in sync 3 times in a row, and display a symbol on the final throw.

Your choices are (quite obviously):

Paper (hand held out flat), Rock (hand in a fist), or Scissors (pointer and middle finger out).

In short,

Paper beats rock ("covers the rock")
Rock beats scissors ("breaks the scissors")
Scissors beat paper ("cut the paper")

If you both throw the same symbol, repeat until someone wins.

Neither of you can figure this out?
Well, then you guys are retards.
Drink. Both of you.