The kennel journal
Puppy Nipping: What Should You Do?

Puppy nipping can be difficult to handle, and yet there is nothing more normal. A puppy discovers the world through its mouth — this is called oral exploration. So your puppy will naturally tend to nip furniture, objects, clothes and your hands. Nipping soothes them while their adult teeth come through, at around four months, but it also lets them interact with you and get your attention.
A dog is an opportunist and has no idea it is doing something inappropriate. Your role is therefore to teach them kindly, by redirecting their attention and offering other kinds of interaction.
How to go about it
Step 1: From the very first nip, stop all contact. Stop playing, stop talking to them, stop looking at them. Ignore them for one to two minutes.
Step 2: Then come back to them and offer a different activity — a chew, a soft toy — while being careful not to wind them straight back up.
Step 3: Praise them with a stroke or a treat. Of course it will not work the first time, but the important thing is to keep going, to stay consistent, and to make sure every member of the household behaves the same way.
This learning phase can include a spike in the behaviour. The puppy will try harder, to see whether pushing gets them what they want. It is important to hold the line and to react the same way every time: first ignore, then offer another activity.
After that phase, the behaviour gradually decreases until it disappears completely.
Worth noting
If a behaviour intensifies, it is because it is being reinforced — in other words, the puppy’s expectations are being met. So the behaviour repeats. If the behaviour brings them something unpleasant, it fades and then stops.
A dog is an opportunist: it will always look for whatever brings the most satisfaction for the least effort.
In conclusion
If my puppy’s nipping is getting worse, it means my attempts to stop it (shouting at them, for example) are being read by the puppy as something positive (I am getting attention), so they carry on. Conversely, if my puppy nips me and I ignore them and end the play session, that is read as unpleasant, so they will drop the nipping in favour of another behaviour that earns treats and affection.