A dog who hangs off your hands, pulls at your sleeves and bites your trouser leg is usually not being aggressive. He is playing. Your hands move, they react, and that makes them the best toy in the house.
So this is not about being strict. It is about making that game boring, and keeping it clear what is a toy and what is not.
Is there growling with it, does he freeze, does he bite when you come near his food or his place, or is he doing it out of fear? Then it is not play and somebody who can see the dog in person should be looking at it. This piece is about the dog who plays with his mouth.
If it is about his food, his bone or his place, that is called resource guarding. It comes from what the owner does more often than people think, usually without meaning it that way. How you prevent it and undo it is coming in a separate explanation. It is not there yet.
Your hands are not a toy
This is the part most people switch on themselves. Rubbing your hand across the floor and letting him chase it, waving your fingers in front of his nose, letting him snap at your hands because it is only play anyway.
To him that is one thing: hands are for chasing. And then it is hard to explain later that it is suddenly not allowed.
So keep it simple and never allow it, not during play and not while he is still small. Play with toys, not with your hands.
What you do in the moment
The moment he bites, you stop giving attention. Fold your arms so your hands are out of sight, and look away. That is all.
What you will see is that he first tries harder. He jumps, he may bark, he comes looking for you. That comes with it: something that always worked suddenly does not. Stay boring, and you will notice he works out fairly quickly that there is nothing to be had.
If he really hurts you, or he keeps going while you stand still, walk out of the room for a moment or go somewhere he cannot reach you. Only come back once he has calmed down.
Negative attention is attention too
This is where it usually goes wrong. Shouting "ouch", pushing him away, grabbing hold of him: it feels like doing something, but to your dog it is exactly what he was after. You react, you move, you talk to him. So biting works.
Here I part ways with some of the advice you find online. The ASPCA and VCA both name a high "ouch" or yelp as a first step, although they then put the weight on the same thing I do: the game stops immediately. Whole Dog Journal writes that such a yelp is as likely to wind an excited puppy up further as it is to slow him down.
That last one is exactly what I see. Which is why I skip that step and go straight to being boring.
Reward the moment he stops
Ignoring him is only half the story. The moment he stops and is calm again, you give him exactly what he was asking for: attention.
That is how you make the connection that matters. Biting gets him nothing, being calm gets him you. That second half is the part most often forgotten, and without it the whole thing takes much longer.
Gentle mouthing and licking come with it
Once he has worked out that biting hard gets him nothing, his mouth does not disappear from the story. He just starts using it differently: taking your hand carefully without any pressure, holding on, licking. Some people call those love bites.
That is not a relapse, it is the sign that it is working. He has learned how much force is and is not allowed, and that is called bite inhibition. Puppies normally learn it from their littermates: bite too hard and the game stops. With you he learns exactly the same thing.
In a spaniel or a retriever you see it even more strongly. They were bred to pick things up and carry them gently, and that shows in how they handle your hand too.
Whether you allow that gentle mouthing is up to you. It is not a problem as long as there is no pressure behind it, but if you would rather not have it at all, you handle it the same way: you become boring the moment his mouth touches your hand.
Offer a toy, but keep it boring
You can give him something he is allowed to bite. That works best when he is wrecking something: you show what is allowed and take away what is not.
Just do not make a party of it. Do not play with it yourself and do not throw it enthusiastically, because then he learns two things you do not want: biting gets me a toy, and that toy means we play together. What you want is for him to be able to entertain himself with it.
So simply put it down on the spot where he was biting, or calmly place it in his mouth, and then step away. That way it stays his toy and not your game.
Long sleeves and long trousers
Something I noticed with Coco: she only bit my sleeves and trouser legs when they were long. If I wore short sleeves, she did not do it.
She probably did not realise my arm was in there. That loose bit of fabric moves, it hangs there invitingly, so in she went. Without that fabric there was nothing to grab.
In the first weeks that is an easy win: wear shorter sleeves and shorts for a while and you simply do not practise a whole lot of repetitions.
Often it is just too little sleep
A dog who bites and is extremely busy at the same time usually does not want to play. He needs to sleep and cannot get there.
That is an important difference, because it decides what you do. Another round of play or another walk makes it worse. Rest is the answer.
Children in the house
I am careful here, because I do not have children myself. What I do know: a child cannot simply become boring and stand still, so you cannot make it depend on that.
Explain it to your child as far as you can, do not leave them alone together, and stay nearby so you can step in on time. That goes both ways. You correct a dog who is hanging off a sleeve, and just as much a child who is doing something the dog clearly does not like.
How long does it take
That depends on why he is doing it. If it is about too much going on and too little sleep, you see it fade as soon as that rest is there.
In a puppy there is something else at play: his teeth changing. According to the AKC the baby teeth start falling out around twelve to sixteen weeks, and the adult set is complete around six months. During that period he has to chew, and then it helps to give him plenty that he is allowed to bite.
As long as you stay consistent, it fades by itself. What takes longest is undoing it in a dog who has learned that biting does get him something.
Frequently asked questions
Why does my dog bite harder when I walk away?
He is usually not biting harder, it only looks that way. Walking away can look like a game at first: you move, so he comes after you. Only once he cannot reach you does he notice it gets him nothing.
If it stays too busy, you can give him a time-out in his own place. After about five minutes you take him out again, as soon as he is calm.
Do watch what that is and what it is not. It is not a punishment, and it only works if he already knows that place as the place where he goes quiet. His crate, his pen or his mat, but one he likes. If he starts crying in there, it is not a reset button and it works against you.
Can I play tug with a dog who bites?
Yes, that is fine. Busy play with his mouth in it is no problem, but only if he also knows when it is finished.
That is the part people skip. Without a clear end he keeps looking for more, and that looking carries on into your sleeve.
How you teach him that finish is coming in a separate explanation about the first exercises. It is not there yet.
Why does my puppy bite mostly in the evening?
That is tiredness. He wants to sleep and does not know how to get there, so he gets busier instead of calmer.
The rules stay the same: you become boring. Only afterwards you send him to his place, or to something else he has already learned means being quiet.
Why does my dog only bite one person in the house?
Because with that person it works. Usually it is whoever reacts most enjoyably, and then it is a fine deal for your dog.
This is one of the things that gets in the way of training most often. If you live together, or somebody comes round regularly who does not stick to your agreements, that is a conversation you have to have. Make clear it is not about being strict, but that otherwise it takes far longer or never works at all.
Being on the same page matters more here than with most other subjects.
Why does my dog jump and snap as soon as we are outside?
That is usually overstimulation and not naughtiness. Too much happens out there at once, and it has to go somewhere.
So the answer is not in the biting itself, but in making the environment quieter and more predictable. Rewarding him for looking at you instead of at whatever passes is the core of that.
And check whether he is simply tired. With a busy dog people often think he needs a walk, while that whole walk is sometimes exactly what he does not need.
How you make the outside world quieter for him is coming in a separate explanation about socialisation. It is not there yet.
Do working dogs and herders bite differently from other dogs?
For almost all dogs this works the same, working dogs and herders included. They are sometimes busier with their mouths, but the rules do not change because of it.
The exception are the dogs bred precisely to bite, like the Belgian Malinois you see with the police. That is not a dog for a beginner and professional guidance belongs with it.
Can I correct my dog with my voice?
Only if he already knows the word no. If he does not know what you mean by it, it is simply attention to him, and then it works exactly the wrong way round.
If he does know it, it is a fine way to get him out of something. But then you taught him that calmly first, at a moment when nothing was going on.
How you teach him a no is coming in a separate explanation about the first exercises. It is not there yet.