I would add...EVERYTHING you see on TV & popular media is for the purpose of promoting promiscuity and a general loosening of standards. The Miley Cyrus thing could indeed be quite a teachable moment.
That’s the way I did it. You don’t need to give your child lectures, just use teachable moments. If you live it, you’ll need to do very little actual lecturing.
Miley Cyrus is a great conversation opener, maybe with, “What is Miley doing that would make a woman like that someone you want to trust?” Once the heart and spirit is right, the physical ideas follow easily. My son just married a wonderful, godly woman who is a true helpmate.