The Chron breaks it down for you: apparently, the questioning young person texts "sexinfo" to (917) 957-4280 on MetroPCS phones or 36617 on other carriers. You'll get a response text (in "teen-friendly text message lingo") asking you to clarify your question, kind of like in those 20 questions toys. Eventually, you'll either get a response to your question or recieve a number to call for more information.
We're neither teen-friendly nor not in a sexual situation at the moment, but that doesn't mean that we can't give this a shot. So, we enter "sexinfo" (no, we do not mean "sewing") into our Cingular phone , and send it to 36617. And we wait. And wait. We check our "sent" messages to see if it went through -- it did.