It's the same concept as training with food.
It's important to let your dog know that you're not trying to take away the toy every time you approach him. Let him have it for a while, pet him while he's playing with the toy. Then out him randomly, don't make it a routine. After he outs (a good out) mark and give it back. Once again, don't make this a routine, do it randomly. He'll never know when he'll get it back, which makes outs better for mine.
Varick vom Haus Jeffery
Dark Sable, intact male
DDR/West German Show Lines