I don't bite my tongue, but I've been biting the inside of my cheeks and front of my mouth for 19 years. Every little piece of flesh ripped off is like a small victory, and more points if it hurts a little. I love the blood from it, no clue why. I feel satisfied chewing the little pieces between my front teeth and sucking as much blood out of the wound that i can. Usually my mouth forms this loose white skin over it the next day, and i repeat the process. I do it when I'm awake only, but it's frequently an unconscious process that I do all day. I have scars from it, and the corners of the inside of my mouth are hardened a bit. I grind my teeth at night for so long that my molars are worn down, and I can't fall asleep with a mouth guard. I do have some tmj from breaking both sides of my jaw when I was 8. I clench my teeth a lot, and chewing gum helps relieve the tension when I've nothing left to chew in my mouth for the day without causing serious damage. Then I start picking my lips. Everyday... How do you stop something that you don't even realize you're doing most of the time when you also enjoy the sensation? Once in a while I cause a sore that swells and becomes painful for a week, but when it's healed, I start all over.