Picture "After beer pong we played a game of throwing ping-pong balls at each other. First to ten won."
Picture "Every time we lost a game, we congratued the other team, and told them 'Good Job! You beat Off in the Shower!"
Picture "The foreign exchange student across the hall didn't understand the concept of knocking, so we gave him a lesson." (I hope this was his knob that you pube'd, otherwise, it just wouldn't make sense.)
Picture "This is what happens when you pass out after too many pints in a foreign land." This takes messing with passed out people to a whole nother level.
Picture Irish ping is played just like normal ping pong, except after you score a point you get to hit the other person in the back with the pong ball as hard as you can hit it.