Whatever your stronger arm is, shove it in the mouth of the dog (your arm is going to get bit to shit), keep pushing it until your are in the dog's throat and try and get it into a headlock with your other arm (if you can). The idea is to get the dog gagging and it'll usually panic. If you can make it throw up, even better: try and suffocate the dog using (sacrificing) your strong arm, its own puke and the headlock.
Pack of dogs, you're generally fucked.
Trained dog, you're generally fucked (they are trained to bite and hold on, so if you try and ram your arm into its throat it'll bite once and not let go).
The more you know...
