[Ostory]

If he likes a ball, then take him out and toss it around. If he will not bring it back, then take a couple. When he has the first one, you turn away from him with the second and toss it up and play with it. He will leave the first, and become more interested in yours. Maybe not right away, but it will happen just keep playing with your ball with your back turned to him. When he leaves his ball toss the second one, and the run over and pick up the first one.

You can wear the out doing this.