Adult Dog Mouthing & Nipping -
With this situation, the adult dogs in question have probably never learned to suppress this ‘antisocial’ behaviour during puppy hood.
It’s likely they haven’t been taught to be gentle or redirected to chew toys instead.
Most mouthing is normal dog behaviour.
However some dogs bite out of fear or frustration and this can be indicative of an issue with aggression.
A playful dog will have a relaxed body and facial muscles. Most of the time an aggressive dog’s body will look stiff and tight - including his or her lips - exposing their teeth.
Playful mouthing is often less painful than aggressive biting.
More damaging, aggressive bites are usually quicker than those that occur in play.
What to do if play biting/mouthing is occurring -
As soon as a play bite occurs on you, immediately cry out in a high pitched yelp! As if you’re hurt (this is an action comparable to what dogs do when playing). Otherwise an “Ahh!” or “Bahh!” firmly.
Praise your dog heartily for stopping (the fright usually does it).
You can resume your play/activity. Repeat up to three times or else see below*.
*If you find a ‘yelp’ alone is proving ineffective, you can switch to ‘Doggy Timeout’ in another room for instance. This is usually for 1-3 minutes (avoiding eye contact, no growling/speaking to your dog) and letting your dog rejoin you only if he or she is behaving acceptably (not scratching at the door, barking) Selina McIntyre, Dog Behavioural Consultant & Dog Trainer, Dogs Best Friend.