By Billy Curtis, Sex Columnist

Sex is one of the most important things you will ever learn about: how to have it, ways to protect yourself from it and, essentially, how to enjoy it.

Last week, I became a teacher, and I don’t think I have ever been so proud of what I write in this column every week.

When teaching someone, it’s not every day that you actually learn something as well. But after receiving an e-mail from a friend describing the conditions I will soon dispense to you, I realized that I had not only learned from my mistakes, but I was helping those around me as well.

My year of celibacy was probably the most profound thing I have done for myself. (This column can be found and is entitled “My Year of Celibacy Ends .”)

It had meant so much to me. But what I would later understand and appreciate more is what my friends would learn from my celibacy.

Sarah was an extremely smart woman. I knew this because we shared a common love for both science and English, and had many conversations in the past ranging from Shakespeare to String Theory.

I didn’t really know what to expect as I opened an e-mail she sent me, as Sarah and I hadn’t spoken for maybe a month or so; because we had both been so busy lately.

I was extremely surprised when I read her first two sentences: “During your year of celibacy, I remember thinking that such a pact seemed completely ridiculous, but it made you happy, so I went along with it. I never understood why on earth someone would purposefully abstain from something as awesome as sex for no apparent reason.” I quickly began to see the reasons for this e-mail.

Sarah had fallen right into my old lifestyle, and as I continued to read the e-mail, I began to realize that my example had given her a new perspective on her life and sexual relationships.

It may have been for a slightly different reason, but in the end, it was all about Sarah’s fears. She went on to write, “I’m sure it won’t be easy at first — I’ve gotten so very used to using men for everything I can get out of them then discarding them out with the condom — but I know I will happier by the end of it.”

After I read this e-mail, I called her and reassured her that it certainly wouldn’t be easy, and like an alcoholic looking for a cheap bottle of booze, the urge to find someone to sleep with would return and crawl right into mind and bed.

But with her strength and the support of her friends, she could quickly learn how to identify and remain in a healthy relationship, where sex is something more than just a one night stand.

She left me with these kind words: “So, thank you in advance for invoking a need to hold myself to a higher standard.” And I don’t think I have ever felt like such an important person to my friends. It felt a hell of a lot better than sex. Well, maybe.

While I was being taught by a student, another one of my friends was learning another important lesson about sex and the power it yields. My friend Ashley had recently broken up with her boyfriend for about the 18th time, and she explained to me that they had another sit-down.

I was ready to start rolling my eyes when she said that they were going to try dating casually again to try and make things work, both in and out of the bedroom.

Then her casual dating partner tried putting the moves on her, asking “Do you want to have sex? Or maybe I could eat you out?”

As much as I hate to say it, I’ve been in the same place with an ex, (well, maybe not the eating-you-out part), but after a breakup it’s understandable for someone to want more of what they can’t have, even if it’s a just “for now” kind of thing.

But Ashley had quickly learned that nothing good ever gets started that way, and she said no. If he wanted it, he was going to have to wait.

It can be a quick fix, or it could be a quick break. Either way, if you don’t learn from your sexual behavior, you’ll be doomed to repeat all the horrible guys and mistakes you did in the past.

It’s easy to see the pattern. It’s not so easy to want to believe it. But when you recognize that it’s bad for you, and learn how to change it, well, what could be better?