Speaking from a purely personal point of view....

I will very rarely advise on cases of aggression or biting. It is irresponsible, I feel, to try to diagnose such problems on the net. The most I will do is, for instance, advise someone to use a house line to remove a dog from a sofa rather than its collar.

However, I feel that advising someone to "bite" their dog, without knowing the person and the dog, and without having a clue as to the circumstances of the dog being a problem, is hugely irresponsible. You risk the dog becoming TRULY aggressive.

The dog as described in the OP is doing typically puppy things which should be perfectly curable WITHOUT punitive methods such as jerking the lead and "biting" with fingers.