In a game or in any situation a passer must be able to communicate with his recievers. Obviously you do not speak directions out loud because the defense will pick up on it.
The way to communicate while passing involves a series of gestures. For the catcher he can either place his hands in the location where he wants the pass or he can point with the hands, eyes or nose in the direction that he wants the ball. The passer can also point with the hands/ball, head, eyes,and nose.