When do you guys start to introduce dummys in training your puppy? My pup is now 3 months old, and we only do play-retrieves with a tennisball for now. I only throw the ball 3-4 times before I put it away to keep the pup "wanting for more" and more exited the next day. This beeing said, for the puppy, it is really a great way to get to exercise on a soft surface (soccer-field). So I would like to throw the ball more, or start using a dummy for several retrieves. Of course just for fun and no steadiness. The pup is really doing well, and if I throw the ball, he will run like crazy after the ball, and deliever to hand every time - either with me calling the whistle, or just clapping my hands and commanding here.
When are we "done" building the desire and can start throwing more and more retrieves?