Puppies are the cutest… Until they chomp your finger. If your puppy is at this stage, you know the feeling. And your playful pup needs to learn to be less mouthy now, before he’s big enough to do some real damage. Mouthing is a normal behaviour in puppies. It often disappears by 4 or 5 months old. If your puppy keeps biting after that, it might be because you’ve rewarded his biting. Use these 3 helpful tips to get your puppy to stop biting.