I think it is very dangerous to tell someone to "bite" over a forum, there are no guarentees they will do it right, and there is a strong possibility it will make a problem worse due to incorrectly used adversion techniques - like the damage that can be done with incorrectly used check chains and prong collars.
They should ONLY be used when trained by a professional in person, not described over the internet - its too open to misinterpretation and misuse. (not that i think they should be used even then but thats neither here nor there)

I dont have a jrt but i do hae a very feisty, strong headed terrier, and dominating techniques just make him push back even more...

personally with a pup that young i would persist with "ow"s and replacing my arm/hand with a puppy teething toy. When buster was a pup, teething kongs and toys were a saviour