If that ever happens to your child or dog, try what this woman did:
I'm not convinced it's going to work in every situation--pitbulls can fight on with horrific injuries--but when you're struggling that long, this might just get the dog's attention enough to end it.
When a Staffordshire Terrior viciously attacked her Jack Russell, Ann Bendouli saved her pet's life by sticking her middle finger up the opposing dog's butt.