When does you dog bite? is it randomly or whilst in play?
Our german shephard (now 2yrs) used to be bad when he was a pup. i believe its a GSD trait & we managed to get rid of it quiet quickly.
You need to either - do the same as his brothers or sisters would have done - squeak (like a puppy in pain) cross your arms & either turn away or stand & walk away, giving no attention for 5minutes.
Do what his mum would have done - yelp in pain grab the scruff of his neck & shake him lifting slightly, then stop & ignore him for 5 mins - this is how his mum would have told him off - it is not cruel as they understand this more than anything else!
The other thing is to remove your pup from the room for 5 mins - jump up lead him outside or into another room with collar & leave for 5mins.
These things show him that he is in the wrong - You can do all 3 intermitently untill you find what that works well for you.
Good luck & let me know how you get on

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