Biting can be an effective form of self defense when done right. Otherwise, you'll lose your teeth or get clobbered. I sparred with my opponent several times and used biting. He came swinging with a bat. I evaded the initial blows, burst in, and trapped his arms to prevent him from attacking. Sometimes, i kneed him in the groin and headbutted him in the face as a distraction before biting him in the neck. If it went full contact, it would've probably severed major arteries and caused death from massive blood loss. Biting is very effective, but also very dangerous. You could lose your teeth and probably get an infection via. AID's and HIV. It should be used very wisely.