It is important to have your dog comfortable in a muzzle. If he ever needs to wear one for any reason you do not want him to be spending his time scratching and trying to get it off.
A muzzle or even a head halter can be very distracting to the dog on the very first time that he wears it. The dog handler in this video is Sit Means Sit Dog Trainer Mackenzie Aeberli. Mackenzie is only 15 years old, and has raised and trained this dog since it was a puppy.