What is a yaoi paddle?

It's a paddle normally with the word "yaoi" on it somewhere and "seme" (top) on one side and "uke" (bottom) on the other. Hitting a character/person on the butt with a certain side makes them that position (or, that's what I've seen at cons. And experienced on myself... ;_; ). Also, I'm assuming that getting hit by a generic "yaoi" paddle makes a guy/male character gay, but I've never been hit by one before. It is the ultimate weapon in a yaoi fangirl's arsenal.