Recently he attacked another young one at the dog school. I don't know how I missed the signs, but there it is, and I need help. I don't know which criteria he has for what he likes and doesn't like, but I wish I did. I am working again intensely on the basic commands, but we have always had a problem with his attention being on me and not on anything else. When we are alone or there are few dogs around, he does everything perfectly. It's the stress situations that are the problem. I probably react differently now too when we see a strange dog. I am trying with treats(I don't use them much in regular training)and praise to keep his attention solely on me when we pass a dog. I try not to put the leash on every time we see a dog I categorize as a potential "candidate" since Nanouk starts looking around "what is there to see..." Strangely enough, he plays again now with the neighbor dog that he stopped playing with when he was a year and a half old.
PLEASE tell me there is a way that I can get this behavior out so that he is again a "playful pup". The hormones may be on their way out, but the behaviour is there.