I totally get it. Have an almost 10 wk old here who is finally by herself. Litter mates were some distraction til yesterday. Now we are in training mode. My recommendation is don't allow it as a baby as the habits tend to escalate.
My littlest girl in the litter was like a pit bull!!!
Never had a pup that bad in my 22+ yrs of breeding. Would never predict it from this breeding either! She'd grab my jeans and just go at it. I finally reached down and tried to pry her jaws and wasn't happening.... Grabbed and squeezed her ear and well, gosh... Magic. Welcome to field training, my dear!!!
Guess what, didnt kill her spirit but made her think twice about that behavior!