Dear Pine90pple,
I hope I can give you some advice;)
I am a recovered bulimic.I went through ten years of hell with this disease and let me tell you..the sooner you ask for help the better.
For me,the thought of asking for help seemed like a scary thing, I felt ashamed of my actions and "what will they say/think about me" kinda thoughts went through my mind every time I thought of seeking help.
Somehow,I decided I needed to do this for myself and made an appoinment with my doc.
I just told him "I have bulimia". That was the simplest way to put it and he took it from there asking questions.
Tell your doctor.He/she should help you look into the kind of help you need.
Whatever your reasons are for doing this to yourself,I can tell you I understand the pain and the unfounded shame that goes with it.This eating disorder served as a distraction from my difficult upbringing but, having gone through self help and recovery gave me the strength to be me, and to express how I feel in healthy ways,using words;)
You are right to not encourage your friend and to "share" information.Maybe the little part of you that feels like giving her "tips" is the wish for someone to share this with as to not feel as lonely? I don't know,but I know that this is a disease,one that can spin out of control quickly so I sure hope you take that first step and tell someone.Also,talk to your friends and if you can,your mom or any other adult in your circle.
It's a beautiful thing that you wish to also help your friend but the first thing to do I believe,is to help yourself.Encourage her to ask for help but focus on getting yourself the help you need and deserve.
I wish you all the best!