WOW ! Some VERY good advice above
One thing is , Dobermans not only need attention -- They demand it = to me , the biting is what he did with his siblings to get them to engage with them to play -- you are taking they place right now .
Every dog needs to chill = you need your space , The best thing I have ever used teaching chill is the " Sit on the dog " training - you don't sit on the dog , but you sit on the leash , Here is how I did it , I did this when I was working on the computer , put his lead on and hooked him up , put him in a down next to the chair , sat down on his lead and then start the clock , you can use whatever time you want to start with , I started with 15 minutes , he had to stay down for that amount of time , the first time , it took me over an hour and a half before he stayed down for that 15 minutes , he gets up , the clock starts over , by the end of the week , he had no problem staying down for 45 minutes - that was my time , his chill time .
Now Little one ( The Warrior Princess ) was a different story , we did the sit on the dog at home , yet at Rally Practice or OB practice she would get nervous , stand , lay down , want to jump on my lap . the head trainer said Ken , she needs to chill , zi told her I was working on that at home , but at home I was missing one BIG thing , there was just Mr. Business there , at practice there may be 10 to 20 other dogs , So I got one of my famous brainstorm ideas and when we went to OB practice , we just went it and sat down , I put her in a down / stay and we just watched all the other dogs go by / practice , the owner / trainer looked over at me and just smiled , she knew what I was doing , the other trainer came over and said you 2 better jump in and join us for some training , I told her we are training , she turned and walked off , for an hour we just sat there and byt the end of class , I had a chilled Dober girl , I have done this several time with her to get her ready for trials .
There were times we went to the little park near us , and just sat and watched people walk by , that can be a hard thing but it works
One last thing
We tend to train all day long , not hard training , like I have them to sit / stay while I feed them . some time next to there bowls , sometimes 20 feet away , just simple things , then at class I tend to only work her no more than an half hour or so , Evie girl can get bored doing the same thing over and over . In Rally we all tend to train up - but it never hurts to drop back down to keep commands sharp .
Best of luck
AND BGpa , that was an outstanding post you put up
