It has nothing to do with being the boss of your dog. I am going to sound like Cesar Milan, but your dog needs rules, boundaries, and limitations, ESPECIALLY around children! Children do things around and to dogs that irritates a dog, hence the nipping and biting that can and will occur. You need to be 150%+ diligent around the dog and children. Your dog is still a pup and needs to be taught bite inhibition and so many things at this age! Have your taken him through any puppy classes? You need to make sure that the kids aren’t bothering the dog, taking his food and toys (could cause major resource guarding in the future), etc. Also, to keep your dog from taking their food, you need to make sure that the dog is in a sit-stay or down-stay (this is where classes come in) when everyone is eating, and to make sure that the kids keep their food out of the dog’s way. Have the children eat food (snacks included) in ONE location, up and away from the dog, like at the table. Puppies see kids as large play toys, and if you do not reign it in and get it under control now, you could have trouble on your hands in the future.
Here is some bitting/nipping info from a thread that I posted to awhile ago. It may not be geared to the age of your puppy, but if you haven’t taken the dog to classes or taught him bite inhibition yet, this may help. You need to make sure ALL MEMBERS of your family do the same things, or it will just confuse the dog and frustrate the dog.
I have never had a puppy (not a big fan of that stage in a dog’s life), but I research dog behavior in all stages.
Puppies chew and nip everything, as it is how they learn about their world. It is completely normal. But it is important to direct the puppy to chewing appropriate items, and that doesn’t include any human body parts! At 15 weeks old, she should have already learned some bite inhibition from her siblings and mother, unless she was pulled away from them too soon. That is a chronic issue with many dogs these days.
You need to teach the puppy appropriate play behavior. It sounds like you are on the right track with what you are doing. To teach the puppy appropriate play behavior, hard biting should elicit a painful shriek or a loud noise from the human, like a rapt “eh eh”. Just like it does with the pup’s siblings or mom, this sends the message to the pup that this behavior is unacceptable. Stop interacting with the puppy. Get up, cross your arms, and walk away, ignoring the puppy for a few. Puppies and older dogs hate to be ignored. Sometimes the worse thing that you can do to a dog (in his mind) is to ignore him when he is just trying to get your attention or play. By walking away or even just crossing your arms and turning your back to him, you have removed the “rewards” (you and the playing), and you are teaching bite inhibition. Gradually decrease the pressure of the bite you permit and add a cue before yelping to teach a signal to the dog. Ignoring the dog is kind of like a time out for humans.
Another way is once there is biting, keep your hands very quiet and still and then redirect the puppy to other appropriate objects. Sometimes shrieking, then ignoring, and then handing the dog something appropriate to chew on is the way to go. Always have something available to transfer to her mouth. It may seem like you are rewarding, but if you do it correctly and with good timing, you are not rewarding.
Other biting, such as on pants leg or a shoelace, can be handled by distractions such as throwing a toy or a simple clap. Remember to NOT engage the dog verbally. Just talking to the dog by saying “no” reinforces the negative behavior. You just paid attention to the dog by opening your mouth to yell at it, so you are reinforcing the behavior. Reinforce only the positive behavior.
I know, it all seems to complicated, but it will work. I have seen it happen and I have trained it. Just take your time and be patient. Dogs are experts at reading our emotions and body language. Reinforcing unwanted behaviors is one of many mistakes we as humans make when raising dogs.