Thinking back, I recall that my own dog went through a "nibbling" phase where she would bite a lot, though this was focused on the feet and more frequently the toes. Where is your German Pincher biting most often? It was a long time ago but I think she eventually outgrew it or my mom used positive reinforcement eg; rewarding her for not biting or stopping after she would loudly say "NO, STOP.". Has your dog had any other behavioral problems, is she an outside or inside pet? All of these factors can influence a dog's behavior. She could just be playing, in that case positive reinforcement might be the best way, she doesn't mean any harm.
