You might have a problem with a rock-eating Papillon. Most likely it is a puppy, or a very young dog.
This can be a very dangerous habit, since these rocks can lodge in his intestinal tract and can set up a live-threatening obstruction.
Most likely it is a behavioral problem for him to eat rocks, only under severe conditions, the underlying problem could be a medical one.
Your dog may eat rocks, when he is:
stressed, bored, under exercised, anxiety.
Punishing, or scolding your Papillon does not change his behavior.
If you see your dog having a rock in his mouth, have your cold water spray bottle ready to spray in his face. If he spits the rock out give him a very good praise.
But all in all, remove the stress, boredom, take him out and play, and exercise him, tire him out, and remove anxiety.
Don't let him eat those rocks. They catch up!!
