First I would try to redirect to a tuggy or toy. If the puppy persists then I would take the collar in both hands and put him in a sit and hold him there til he calms down then just release the collar and move away. Do not turn him loose to move away. If he comes after you repeat. It won't be long til he decides that is not fun and he will stop or redirect to the toy. If he really persists and actually makes contact then I would squeeze the muzzle and say NO biting firmly but calmly then put him in the sit til he calms down. It won't take but one or two times of this and he will decide that there are better things to do.
I know there are a lot of folks who use the walk away method but it does not stop the problem. For dogs, they see in pictures, so if the picture looks the same then they respond accordingly. If they see you retreat then they win. Little dogs might respond to this I don't know because I don't train or work with small dogs much. Usually the dogs in my classes are larger. But I have seen so many out of control little dogs I suspect that there would be better ways to handle it. Same with saying OUCH. The alpha never whines or cry out. They remain strong and confident in their ability to handle the situation and so must you. Your wife needs to get on the same page or she will have issues later. Dobermans are very willing to follow a leader that they trust and respect. They do not respect or follow weakness. So everyone needs to step up to the plate. Obedience does not mean punishment in a heavy handed way. It just means correct guidance that the dog clearly understands.
Thank you very much for the detailed post. This will be our next project. It's amazing how stubborn these dogs can be. Hahah
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