Group classes are good. My 10month old is full of energy too. However she is very good with other dogs. You describe mounting behavior, which is a dominant act. It would be better the have Maverick with the same dogs frequently, so he gets to know them. I go to a dog class every week. We practice socialization in the beginning of the class, then stay, short leash, long leash, depending on the dogs level. The last 20 minutes they get free play, which is great for a high energy dog. The gentle leader is a god send for controlling the head, the pulling. Make sure he has a good solid sit and don't let him get close enough to mount another dog. You can greet another owner at 6 feet, put your dog in a sit. Talk to the human and slowly approach inch by inch. That is what we do in class and my energetic GSD is very good. Once he has his sit stay and down stay in place, take him to shopping centers. I got a year old male that had never been trained and he became a perfect gentleman. I took him to a shopping area every day for 15 minutes. The entire training took a full year, but at the end I could take that dog anywhere. I am repeating the same with Heidi, take her into banks, hardware stores, the post office, etc. There s nothing like a well trained GSD. Other wise people will be afraid of Maverick, which is not a good thing. BTW, Wolfgang was my first GSD, and I hired a professional trainer for 10 weeks, she came to my house every week and I would practice in between, and take him into public. One final thing, is he neutered? it would be a good idea and he is the right age. I am on GSD # 4 and have used the techniques I learned from the first trainer on all my dogs.