For the out, I pair the action and thought process of the dog dropping the first toy to get the second one. When I see the mouth start to open as the dog is running back to me, and the dog is about to drop the ball in it's mouth, I say "out." I make an association with the command and the action the dog is already doing. The dog is already thinking about dropping what is in it's mouth and I simply pair the command with that thought process.
I do not try to teach an out with a dog that is tugging. I do use a ball on a rope or a kong on a rope for the two ball game. I have found that when a dog is tugging it is counterproductive to even say "out" because a different association is made. The new association is "out" means tug harder. This directly corresponds to bite work and releasing a bite. I find that dogs taught the two ball game and learn to out the toy, out in bite work much cleaner, quicker and with out any conflict.
I agree with marking the "out" once they drop it, that is the key. I just do it a little sooner. When the dog is about to open it's mouth and release. Here again, it's all about the timing. My dogs would be reluctant to let go if there was any tension on the rope. They would also tug hard, causing movement and the game is on again. Once they know the out, then I release tension on the rope and say out and they will release.
With stubborn dogs or new dogs, I simply pull out the second toy and make that one really exciting, get the dog interested and then reward when it drops the first toy.
With the new dog, Boru, I run the risk of getting tagged over a toy. It has gotten much better, but corrections over a toy will cause him to redirect. I simply tell him "LOS" or out, step away, command him to down or return to heel and he complies quickly. I then command stay, pick up the toy and go back to work or reward. I have made progress where he will drop a toy into my hand, but telling him to out and stay is very manageable. Allowing him to do tug wouldn't work, he would do it all day. He's a little OCD and ADHD with toys.
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