Get your dog used to the dumbbell by presenting it to your dog and clicking every time he has a positive reaction. A positive reaction would be sniffing the dumbbell or putting the bit part of the dumbbell in his mouth instead of the bell part of the dumbbell.
Repeat this introduction process several times with a click treat reward. Introduce the dumbbell, let your dog sniff, and click and treat.
Once your dog is used to the dumbbell, have him hold the dumbbell in proper positioning. Avoid allowing your dog to mouth the object. You want the dog to hold the dumbbell in his mouth without gnawing or chewing on it.
Each time your dog correctly holds the dumbbell in his mouth, click and treat.
Distract your dog while placing the dumbbell in a position where he must find it.
Walk with your dog to the dumbbell.
Using a verbal command such as “dumbbell” or “fetch dumbbell,” and encourage your dog to put the dumbbell in his mouth.
Click and treat once he puts the dumbbell in his mouth.
Repeat these steps until your dog automatically puts the dumbbell in his mouth without coaxing him to do so.
Click and treat after a positive mouth hold.
Move on to the next step by tossing the dumbbell a few feet away.
Using verbal commands, ask your dog to fetch the dumbbell.
Once your dog has retrieved the dumbbell and put it in his mouth, click and treat immediately by walking toward him with a treat reward.
As he becomes comfortable with this retrieval process and his click and treat rewards, begin to have him bring the dumbbell back to you.
Toss the dumbbell. Staying in place this time, ask your dog to retrieve the dumbbell with your verbal command. “fetch dumbbell.”
This may take a few times, but if you are not moving, he will be encouraged by past behavior to bring the dumbbell to you seeking the reward of a click and treat.
Once you have the dumbbell back in your possession, click and treat.
Continue working this process with your dog until it is second nature for him.