Even a gentle dog can get overexcited when playing. If the dog has not been taught to keep his teeth off you, he can escalate gentle mouthing to a painful bite in no time. When your puppy nips, tell him “No!” If he nips again, tell him “No” again, stopping him physically with your hands. This means you can hold him off by his collar.
Do not hold his mouth shut. This frustrates him so much that he loses the connection between the nip and the correction in his struggle to get out of your grasp. Better than that, if he keeps at it, grasp his collar and shake him. After the shake, if he's nipping again, put him in his crate to cool off.
Confining your dog to his crate as a punishment is effective. It will not make him hate his den. After all, when you were a kid and you were being punished, you may very well have been sent to your room for a while. Did it make you hate your room? Certainly not. Like you, dogs have a sense of fairness. If your correction is clear, your dog will accept it with calmness. If you are vague, how can the puppy understand why he is being punished? He doesn't know what he did to deserve your wrath and he doesn't know how to avoid it next time.
But if you are clear about what you don't like, your correction will be understood as follows: "Listen, Laddy, I've asked you three times not to exercise your sharp, little teeth on my hands. But you refuse to stop. If that's the way you're going to be, I won't play with you for a while. Go stay in your house and think it over!" Healthy, loved puppies are very forgiving creatures. Correct fairly and your puppy will both learn and continue to love you. He will not hate you for exercising your right to teach and lead.
You are going to use the crate not only as a den and a bedroom, but as your main tool for prevention of dog problems and one of your chief methods of correction. Using the crate lets him know that he cannot act in certain ways in your house. The crate, on the other hand, is his house. You should respect that fact, too, and let him be when he's in it. Leave him alone when he's there. On his own, he will use his crate when he wants peace and quiet. He'll go in it to rest and to get away from everybody.
When he's not in the crate, keep the door open and let his house remain accessible. Keep it clean, washing it out once in a while or vacuuming out the hair. When you clean your house, put his toys in his crate. That gives a strong, positive message that this space is yours. When you think about it, there isn't too much a puppy can call his own. Give your pet his own room, it will make him feel extra special.
