Sex: There's no single way to do it "right" but there are lots of ways to do it wrong. Not being respectful and tender towards your partner is usually at the root of "wrong" ways to do it. Also, there is no rush. You may think all your friends are "doing it." They're not. Take your time.
Talk about how choices become habits. Habits can become addictions. Describe how pathways are literally dug into the brain and it's very hard to change them once those paths are made.
Be yourself. No need to pretend to like something the crowd is doing. Half of them are probably just as unenthused as you are but are afraid to say so.
Never make someone feel bad for liking something. Not your kids, your friends or colleagues. Joy is a beautiful thing. Cherish it in yourself and in others.
When you see someone in military uniform, thank them for their service. Hold the door open for them, etc. If they are behind you in line at Starbucks, pay for their coffee. At the very least, look them in the eye and smile - they’ve made a tremendous sacrifice and you should acknowledge that.