BlueEyes is right in that baking soda will help cut the acid that builds in your mouth after purging, but you WILL damage your teeth anyway. I never had a single cavity until I became bulimic/anorexic. I've been recovered for 3 yrs now, and my dentist still finds tiny cavities during each visit.
Do you want to get better? It's ok to say no -- it takes some time until you realize that you need to get better. The reason I'm asking is b/c your posts (this one, and the one about being thirsty) regarding bulimia seem rather flippant. So, are you in the stage that you want help, or are you in the stage that you still want weight loss tips?