My Pug likes to bite.

Question
I have a 12 week old male pug puppy.
He is teething. He has a habbit when he
plays to jump up on you and bite your
legs,face,neck,arms, ect. He does this over and over until you just want to get up and walk away
from him.
I say "NO!" But he does not seem to care. I looked up other info on this and I saw that "scruffing them and pinning them down until they relax works on one web sight." They said to treat the puppy like the mother would treat it. My nabor tells me to hit him on the nose. I could never do that to a little puppy. I need to know the best way to tell a dog "NO" with out it causing long term mental damage to my dog. I want the dog to trust me. I know what ever I do to him as a puppy will not be forgiven as an adult. What is the best way to teach the dog NO?
Also (side question) How many voice comands can a dog learn?

Answer
Hi there. Let me first start with the most imprtant part of this question. NEVER hit your pug on the nose. The wrong angle and force of a hit can cause your pug to die instantly. Their noses can't handle it.
Honestly, biting and chewing is all about puppies. There's really no sure-fire way to get them to stop. When they start chewing, just try and give them a toy and have them chew on that instead, showing them that that's what is right to chew on. If that doesn't work then you're just going to have to put up with it. My pug Bella is still in her teething stage, and I've gotten used to it by now. It's annoying, but it'll pass. It's just part of owning a puppy, and something you should have known about before you bought him. But understand that discipline (though not too harsh) is a good way of establishing your dominance over the dog, and they won't hate you for it!
For your side question, dogs can learn anything if you spend enough time on it. There's no numbers or anything. But it is hard to teach them lots of stuff. Especially pugs who are kown for being stubborn. Good luck!