The things that stick most in my memory about any of my dogs are the ones that made me laugh. When my darling Schara was a puppy she once came running up to me as I sat at the computer, bit me hard on the thigh, whirled and ran off as fast as she could go. It hurt and later proved to have marked my thigh through my jeans but didn't break the skin, yet the way she did it with such joy had me biting my lips to keep from laughing out loud. I didn't go after her but sat there lecturing myself on how I had to stop behavior like that no matter how cute and funny and that she'd probably do it again soon if I gave her the chance.
Sure enough, she came zooming back for another try before long. I managed to grab her, lifted her front end right off the ground, took hold of neck scruff on each side of her face, gave her a hard shake and nasty "No" before letting her down. It didn't stop all puppy biting on the spot but it did stop that particular game. I know those kind of corrections have gone out of style, but done right they sure are effective, and I'm still not against using them on tough-minded breeds like my Rotties and your GSDs.
Sure enough, she came zooming back for another try before long. I managed to grab her, lifted her front end right off the ground, took hold of neck scruff on each side of her face, gave her a hard shake and nasty "No" before letting her down. It didn't stop all puppy biting on the spot but it did stop that particular game. I know those kind of corrections have gone out of style, but done right they sure are effective, and I'm still not against using them on tough-minded breeds like my Rotties and your GSDs.