First, a girl has to be on the opposite side of the room that you are. Then you tell her to drop to her knees, facing you, and open her mouth as wide as possible, thus creating a bigger target. Next, you have to take the biggest/longest shit possible into the palm of your hand. After you have done that, you wind up, and take one step foward to create momentum. Finally you javelin your shit into the girl's mouth.
Dude, my girlfriend's mouth still smells like my shit from that Jamaican Javelin i gave her last night.