Bonnie and Chu

(You happen to come upon the girls room. They see you and become excited. You see the sign and it says they'll give you a unique prize if you can guess what they are doing or what item they are trying to show you. They smile at each other and decided to tease you. Bonnie makes a fist and does a jerking motion then gives it to chu. Chu proceeds to put her hands in a fist one on top of the other and move it up and down in another jerking motion. They both smile as they wait for you to guess.)