Instructions
Hold one end ball in each hand. The third ball will hang loosely along the cord, making a V with the Astrojax in front of you.
Drop one ball, putting the Astrojax into a swinging motion. Raise the hand still holding a ball. (It is best to use your dominant/throwing hand).
Move the ball in your hand in a flat circle in front of you and watch the Astrojax follow. Don't let the Astrojax swing up and hit your arm or part of your body.
Try a circle to your side: Hold both end balls in one hand, release one, bring your hand up as if doing a circle in front of you, and make a small circle. The Astrojax will follow, making a larger circle off to the side. Again, hold the Astrojax far enough from your body that it won't strike you.
Experiment to come up with other tricks. Because the third ball slides freely along the cord, it will change the trajectory and force of the cord as you swing the Astrojax. To get an idea of its use, hold an end ball in one hand and the middle ball midway down the cord below the other ball. Let go of the middle ball and begin moving your hand in circles parallel to the ground before the ball slides down to the end of the cord. The middle ball will swing out farther than the two end balls, and the Astrojax will make a motion resembling a lasso.