Used in the binge-drinking themed sport of Beer Pong. While the game of beer pong requires that a ping pong ball be thrown from opposite ends of a table into solo drinking cups filled to a level with domestic beer; throwing a "Dirty Ball" is to toss a ping pong ball without rinsing it in the designated "water cup" with the intent of fouling the opponents domestic beer filled cup without their knowledge.
So what, I threw a dirtyball, they were winning by 3 cups and I was wasted!
The act of positioning ones self and exposing ones genitals to distract an opposing player that is engaged in shooting the eight ball in a game of bar pool.
Egan: Hey did you win that game?
Ray: Yeah, guy was going for the win so I gave him a dirty eight ball and he scratched!
Egan: Haha fuckin right!
Ray: Fuckin A, I won two bucks!
When your girl or side hoe takes a cup of confetti and has you cum in it and then puts it in her mouth. After that she engulfs your scrotum and continues to gargle on it until the sticky confetti sticks on to you giving the appearance of a disco ball.
After arts and crafts with my daughter, she gave me a Dirty Disco Ball.