Have you checked out the sticky "The Bite Stops Here"? It has some great info. Do you know much about his background? Puppies usually learn bite inhibition from their mamas and brothers and sisters, and then we humans add to it with training. But, if he's 10 months and already spent at least 2 of those months as a foster with you, it's doubtful that he's ever received that kind of training.
The basic idea of "The Bite Stops Here" is that you let him know when he bites too hard by making a sound, and then if he does it again, you leave the area/room so that he knows human contact ends when he bites hard. Here are some thoughts:
- usually the noise recommended is a high pitched yelp, but some pups get more excited when you yelp, so some people prefer a loud (but not angry) OUCH! or HEY!.
- whatever noise you choose, be consistent, and make it EVERY time the biting is too hard.
- the noise should be loud enough to get his attention and make him stop, even for a split second, to see where the noise came from. If he doesn't pay attention to the noise, you may have to try a different noise.
- if he goes right back to biting, make the noise again, and leave the room, for 30 seconds or so.
- if he does it right away, AGAIN, make the noise, and this time leave for 45 seconds. Gradually lengthen the time you stay out of the room by 15 seconds or so.