That was the weirdest possible way to defend her own dog. Why didn't she just hit it with a stick as said above or kick it. Putting your face near a blood thirsty pitbull isn't exactly a logical approach. Maybe she was a dog in her former life.
Actually I have heard the 'biting' a dog theory by many people who know dogs, never tried it myself. Gutsy, but perhaps the best approach..
This reminds of one time when I was at the beach, the lifegaurd got bit by a jellyfish and picket it up and bit it back (Brilliant!) - the dog will probably die - the human mouth is filthy
Comedian, Frank Skinner suggested inserting a finger in the other end of a pitbull if it's jaw locks. It (should) then release it grip. Would that mean the dog would get the (digital) point?