Ok what I'm going to say now are "my" thoughts on this,... just so you know, I don't have experience with very aggressive dogs.
Take my advice for what it's worth
This is what I learned from all the reading on this site and the DVD's: the dominance issues would be solved by corrections, but the fear involved should subside once the dog sees that you're confident and in control.
Try to aggressively chase away any approaching dog, even friendly ones. From your dog's point of view, an overly forward friendly dog might seem threatening.
If it's a person and you want to talk to them, correct the dog until it stops its aggression and get it to sit, or better yet, lie down. Don't praise for stopping the aggression; it's inappropriate pack behaviour.
Once you convince your dog that you will not tolerate him to act aggressively and that you will quickly and effectively deal with any threats, he will relax and not worry about defending himself.
He may always be dog-aggressive, which is why you should avoid dog parks and unknown dogs, but at least when he's by your side, he should eventually learn to look to you when a strange dog approaches. You'll certainly have a much easier time controlling him.
So even if he's acting out of fear (understandable after what he's gone through), correct him, get his attention onto you and immediately chase the other dog away (tie your dog to a tree if you have to so he doesn't run past you to attack the other dog).
Don't praise him; just act as calmly as you can and walk on without making a fuss.
If he starts looking intently at another dog in the distance, again, correct him until he looks to you. Then, no praise, just walk on. If you're worried that he's getting upset from all the corrections, throw in some motivational obedience work when he's being good and play with him.
That's the best way to "comfort" him.
Unfortunately I made the same mistakes with my female shepherd back when she was young. I was told by the local obedience trainers that I had to socialize my pup with other dogs at the park. I was told to let her run with the dogs and let them work it out amongst themselves.
Inevitably, she had bad experiences (even attacked by a pitbull once; the dog was out of control and wouldn't listen to its owner. It only stopped the attack when I stepped in and lifted it off the ground by its collar and it started choking. Can you believe it? The owner standing there not doing anything while watching a 12-year-old child (me) trying to stop an attack from her aggressive pitbull!). My dog ended up with a bite wound on her ear...
Luckily my female was never badly hurt (physically) during these encounters, but she was bullied a number of times by packs of dogs that would pick on her.
She eventually became so fearful that she would refuse to enter parks if there were many dogs there. If we kept going without her, she would circle very far around the dogs and meet up with us after we'd passed them. All the "trainers" said to us was that some dogs are more "naturally submissive and fearful" than others and that this was a temperament flaw often seen in shepherds.
(The more I think about all the advice I received back then from so-called professionals, the more I want revenge!!! I was only 11 years old when I got my female; my critical thinking abilities weren't developed yet and I believed everything they told me.)
Anyway, as a result she developed aggression issues with dogs. She takes it upon herself to charge at them and will pin them to the ground, snarling.
After trying out Ed's methods she's improved significantly. She no longer seems worried about meeting new dogs and has stopped being aggressive with them. Now if she doesn't like a particular dog approaching her, she'll look over to me and watch in satisfaction as I drive the dog away.
It usually doesn't take much to drive away the average pet dog; just stand between your dog and the other one, stare at it and speak in a deep serious voice.
Heck, in many cases you'll get the strange dog to obey your commands when it will gleefully ignore its own owner!
(A lot of weak pack leaders amongst the local dog owners where I live
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It was the easiest thing I ever did and certainly the most effective way to get my female shepherd to relax on walks. As for my puppy, he automatically looks to me when we're approached by strange dogs. He doesn't get nervous at all, even when we walk by aggressive dogs that are barking and growling at us. He knows I'll protect the "pack" and he feels secure.
As I said, no matter how much you read on the site, the dominant dog DVD will give a lot more insight on the matter and shows you the right and wrong ways to give corrections.
You'll be surprised at just how much insight Ed has on the matter and how much it all makes sense.
You sound perfectly capable of dealing with your dog, and in fact you already seem to be doing a pretty good job
With the extra information I'm sure you'll be able to fix this.
(Sorry for writing a book; I'm getting all worked up and angry when thinking back to what we put our poor female through over the years. I'm done venting
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