Ask a Dog Vet and Get Answers to Your Dog Veterinary Questions
I am sorry to hear you are worried about Smudge the Pug. I am a veterinarian and will do my best to help.
How long has he been like this?
He might be having trouble with passing pieces of bone, or the bone might be irritating the lining of his intestines as it passes. I might consider not giving the bones again; the veterinary dentists tell us not to give anything to our dogs that we can't bend or break with our bare hands because it can cause fractures of the teeth.
He might have problems with his anal glands being impacted, or infected. When I see a dog rocking on his rear end, I always check the anal glands. If his glands are little inflamed or impacted, they might hurt more as the pieces of the bones pass by. These glands are inside the anus, you can see them from outside. I check them, wearing a glove, inside the anus.
Let me know what else I can help with or answer.