No Bad Looks
If you've never owned a dog before, or a boxer, you may not be aware that as the young males, and sometimes females, come into late adolescence/early adulthood, they will decide that they need to stand their ground territorially, which tends to extend to wherever they are. In these situations, they will often assume a particular stance and stare out at the world. This is an invitation to mayhem in dog language, or at least to a challenge from other equally immature young males (for the most part). Your job, as the owner, is to be aware of this type of look and to nip it in the bud.
Rather than let your boxer get the adrenaline rush of skirmish, which can be quite addictive, you can, when you identify that look and posture, correct him, distract him from staring at the other dog, and say, “No bad looks.” Obviously, you want to distract him in every way possible, and you might want to move out of the other dog's line of sight altogether, if possible. And obviously, you want to reward him when he breaks off a bad look!
Don't let another dog lock eyes with your boxer or vice versa. Boxers are notorious not for starting fights, but for finishing them. The best way to avoid the negative ramifications that go with a skirmish is to block eye contact. Most dogs will give up the bad impulses once eye contact is broken. If another dog does engage your boxer in a skirmish, if you can throw a jacket or towel over their eyes so they can't see each other, you have a good chance of extinguishing the problem.
You can start this training when he is a puppy if he occasionally gets to be too stern or rough or dominant with other puppies and dogs. No one likes a boxer that is a bully, and the “No bad looks” command, incorporated with “Leave it,” is probably the best possible guarantee you will ever have to help ensure that your boxer will never be involved in a fight.

