I know my GSD is still a baby and will of course bite because she is teething. I have given her chew toys and she enjoys chewing them for a while. but i am having problems with teaching her that biting me and biting the other dogs is not ok. She bites in a playful way, but sometimes she bites a little too hard for me. Ive tried the flick on the nose and the holding the muzzle shut and saying "no" methods but it just makes her want to bite even more. When I hold her muzzle closed for a few seconds, she cries a little and when I let go, she immediately tries to bite me. (I'm not hurting her btw, I'm barely applying any pressure to her muzzle). Any suggestions?