That's one reason why I personally don't like a harness. Not that they are inherently bad just that, you can't really communicate well with your dog that way. It makes them believe they have too much control. It's mental. Dogs WANT to be told what to do. It's in their nature.
But, they aren't going to listen to you if they don't believe you or trust you. In fact they will make their own decisions if you don't make them for them or teach them what a good decision is. If they feel they are left to come up with their own decision, it's not comfortable for them. When they are uncomfortable they can be scared, fearful, aggressive. They can become confident, domineering, snobby, and greedy too. Any combination.
IF they aren't told to behave and MADE to behave a certain way, or believe that you will make them. They do it their way. You don't choose.
In my mind If I had a front hook harness in a bad situation I would pull HARD to make the dog face me. But you can't do that if you are afraid He's gonna bite your face. He will feel as if you are not in control to begin with, you pull him around to face you, breaking his chain of thought. But if you're projecting fear and he feels HE has to make a decision. It may not be the desirable one.
If you are afraid he's gonna bite you, and you DON'T 100% break the thought process he is determined is going to play out, he just might. He has no confidence or trust in his handler. I'm not saying it's your fault, you haven't had him that long. The longer they have a habit or a "belief"(that humans can't handle the situation) the more he will feel its up to him to handle it.
So if you ARE afraid def put a muzzle on before doing anything I say lol. IF you think he will bite it's a necessary precaution. You don't want to be in a critical situation and not be able to physically control him AND mentally control him, it could end poorly.
By escalating I mean in tone, posture, and if necessary escalate to physical contact (not pain). You aren't trying to hurt him, and if you can't physically force him to do anything this method wouldn't work anyways. But basically if he's being aggressive you have to make him believe that's unacceptable and to stop immediately. You can't make him do anything if he's in control. He either decides to do as you command and if he won't either by choice or by not knowing the difference. You force submission.
The most submissive position they could be in is a down. Even more submissive than that is on the side( paws not on ground) or on their back. In a way it makes them feel helpless if they are forced into this position (physically or mentally). Feeling helpless means they are not in control. If they aren't in control, and you put them in a helpless position than... The only conclusion can be that YOU are in control.
They may not like that. They may indeed bite. Shit's not pretty but that's why you don't see videos of how they ACTUALLY stop aggression for good. They show you AFTER they make them submit. You are not alpha if dog does not submit to you on command. That's dog behavior. You see dogs interact in that exact way all the time.
Older dog gets growly, younger dog submits. Alpha dog projects power and confidence, the others follow. Dog pulls you down the street on a harness acting aggressive towards others, making his own decisions. Who's following?
It's all connected. They don't associate with rewards or treats with outside entities. They associate with their own behaviors and feelings, and beliefs. Dogs take everything personally. Usually they only think about themselves. If they think they can take care of themselves better than you can, they will try.
One way to help you get a HUGE dog like a mastiff down into a submissive position with less physical strength is to actually reach across their chest and grab their front opposite leg and use your weight to push them that way. This is very close and personal position to be in and if you think the dog will bite please use a damn muzzle. I won't be responsible for you trying to help a dog on my advice and have your face bit off.
This is all of course assuming when aggression starts you have absolutely no control other than holding on to the leash, yelling, and projecting fear. If all it takes is a poke with two fingers in his side to break his attention and stop the aggression great. If all it takes is a verbal command great. But by escalate I mean you must control the situation no matter what it takes or find someone who can. Not by fear or pain but as a simple matter of FACT.
Otherwise the dog will continue to make it's own decisions.
