You need 2 people for this- one of whom must be able to produce cum on demand. First, let the man fill a cup with a ton of lemonade. Put a top on this cup and then jerk off into another cup, putting a top on when you are done. You must now have another person take a guess what to drink: either receiving the lemonade or the Ejaculation Special.
The Ejaculation Special is my favorite game.