4 year old German Shepherd Entire Male

Question
QUESTION: Last week at socialisation/obedience class my German Shepherd attacked a king Charles spaniel (who he was friends with, and did not provoke him in the slightest) who then had to spend two days at the vet and have stitches. Two days later, whilst out walking with him a Norfolk Terrier tried to bite him (my dog on lead, the other off lead) so he picked it up and shook it (which is what he did the the king Charles spaniel). He shook it about three times then put it down where upon it scampered off whimpering.A week later he tried to pick up another terrier, totally unprovoked (deaf 15 year old neighbours pet).95% of dogs we meet are aggressive toward my dog although he never appears to show aggression first, he is always excited and happy to see another dog, then they get closer and are aggressive to him, where upon he defends himself. (except of course for the two unprovoked attacks) He has never been interested in females particularly, even when the Labrador next door was in season, he didn't act any differently towards her. However, he has started to masturbate quite a lot, one of the triggers is when he is being groomed.. he dashes off whimpering (even though I am nowhere near his nether regions) and spends about 10 minutes constantly relieving himself. He has also started turning his lip up and growling at my daughter and husband when they try to put him in his kennel/run for his breakfast, or make him do something that he doesn't want to do, although he has never done this to me.  He loves his run (1/4 acre)and stable and is quite happy to be in there, I have been walking him for an hour every day although he doesn't seem to mind if he goes or not. If he doesn't go out for a walk, I have him out in the paddocks and we play ball or do training together. Should I have him neutered? Would it help? I dare not take him back to training. It was so distressing.I don't know how to handle this. Any advice would be greatly appreciated. Thanks

ANSWER: Yes, go ahead and neuter him.  It should help, although not right away, and he will require more training.  The class would have been good, but you will have to continue without it.  The key to most behavior problems is approaching things using the dog's natural instincts. Dogs see all the people and dogs in the household as a pack with each having their own rank in the pack and a top dog. Life is much easier if the 2 legged pack members outrank the 4 legged ones. You can learn to play the role of top dog by reading some books or going to a good obedience class. A good obedience class or book is about you being top dog, not about rewarding standard commands with a treat.

There are 2 trends in dog training now.  One wants to abandon the concepts of leadership, and the other to return to the failed, harsh methods of the 50's.  Avoid both.  That is a difficult problem, perhaps more than what I can give you over the net to solve.  You may have to find a private trainer.  Good ones are hard to find.  

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QUESTION: Thank you for your prompt reply.
I have paid or a private trainer who advised me to have him put to sleep, which I will not do as I realise that it is us who have the  problem, not the dog. I have tried other classes but to no avail.
Would you recommend an APDT trainer?, or Jan Fennell trainer? Thank you for your time and patience.
Regards
Julie Hitchcock

Answer
I am not familiar with Jan Fennel, but have heard good things about her.  Could be worth a try.  With the APDT, at least you will avoid the 50's.  You risk over reliance on treats and pyscho babble.  

Perhaps with any book you should turn to the back and if it is so jargon filled you can't understand it, try another.  Same with talking to a trainer.