Porn: I wish I could keep you away from it entirely but at least I will prepare you.
It’s normal to be curious, etc. but like anything else, it can get to be too much and can be very harmful, especially to a very young person. It can disrupt your healthy sexuality, ruin your relationships and even your career (no porn at work!)
Also keep in mind it is a business designed to make money, not to be realistic. That's not the way sex looks. Also the women are NOT enjoying themselves.
So try to avoid it, but at least keep it to a minimum!
Things are rarely perfect, but things that are less-than-ideal aren't all bad to the same degree. Let's talk about making buckets for "not ideal but I can put up with it" and "deal-breaker." Works for all kinds of situations. Another variation of this is to grade the suckiness of a situation on a scale of 1-10. Have them decide at what point action is needed vs. just putting up with it. This one works well for hunger. Yes, you're hungry, but on a scale of 1-10, how hungry? It also works for relationships! There are plenty of things about a spouse that are less than ideal, but how many are true deal-breakers? Teach them to understand the difference.
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.