Become educated about sex and relationships.
Every time you feel like you want to have sex and if you are with someone get around many people. Always stay in public places with people you think you might want to have sex with.
Change what your doing to avoid getting sexual. You know?
Such as keep a paper on risk like Rob said. Read that paper if you think your going to fall. Likewise you can use anything. Bible, or whatever.
I wouldn't have sex and regret all what I have done, because holding the hand of a love on is better than sex if you ask me.
Every time I have sex I regret it. It is not the one. Sex feels better when you love the person, but likewise sex isn't everything.