During the Passover Seder, the "story" of the four sons is told. (If you don't know what this is, go
here. The story is pretty much the same as I'd heard for the last multitude of years. Dunno about the commentary though.) Don't ask me why I thought of this (Thank you Alfred Kinsey) but it struck me that the way the four sons react to Passover could also be applied to sex ed.
So
The Torah refers to four sons: One wise, one wicked, one simple and one who does not know how to ask a question.
What does the wise son say? "What are the testimonials, statutes and laws Hashem our G-d commanded you?" You should tell him about all the variances of sex from vanillia to the most obscure fetish, from long-term monogamous commitment to one-night stands.
What does the wicked son say? "What does this STD crap mean to you?" To you and not to him. Since he excludes himself from the community, you should tatto a mark across his forehead warning everyone that he encounters that this guy might just be a rutting Typhoid Mary. But you don't because that wouldn't be nice (or legal.) You should blunt his teeth by saying to him: "It is for the sake of your partner(s) that I am telling you this." For them and not for him. Maybe if he starts thinking about long-term consequences he'll get a clue.
What does the simple son say? "What's this?" You should say to him "Sex is something that people who love each other very much do. It also has some long-term consequences. Here's a bananna; let's try putting a condom on it."
And the one who does not know how to ask, you start for him, as the Torah says: "When you have a question, I'll try and give you whatever information you can absorb."
Or something like that. Probably a little too harsh for the wicked son, though.