I don't actually agree with the common rating systems that are used. I comply with them, so that people know what they're getting into, but I think they're over-simplifications that don't really tell you what's in a story, or what's appropriate or inappropriate for kids.
I have four "NC-17" or "High R" stories that I consider to be very appropriate for teenagers. They don't ignore that teenagers are interested in and are probably having sex (I'm including both second and third base here, guys, and don't tell me that's not sex Mr Clinton ;).
NC-17/High-R Fics of mine teenagers should read:Skinny Dipping -
Not everyone's how they seem. Image is so important in high school and here Harry has a chance to see past the surface of one Percy Weasley. The sex is warm, sensual exploration, gentle and positive, but not romantic nirvana (note the pondscum): it's simply normal.
Hagrid's Hut -
Relationships can be caring, but unequal.I've been flamed for this story, not because of the explicit sex, but because Harry loves Ron more than Ron loves him. This ruins the romanticism of the pairing; it's unfair, but true to life, as any broken-hearted teenager can tell you. It doesn't mean that Ron doesn't care, they are still warm and gentle with each other. But most know that Harry will have to go elsewhere.
Rising Sun -
Too much, too soon, spells disaster. This about teenagers who have sex before the relationship's stable or they're mature enough to handle the emotional fall out. It's also about the double standards for boys and girls, and the difference in their attitudes about sex. Once again, it shoots down the idea of sexual nirvana that's portrayed in the media and it makes a case for waiting.
Sweet Hypocrisy -
Honesty hurts, but it's best in the long run.This is a coming out story, where a young Percy about to make some serious mistakes is forced to admit the truth. This is the most borderline of this group, because Snape is as usual in a moral grey area: on the one hand his actions are morally reprehensible. On the other, his motives are absolutely clean. There is another message buried in this fic, that one can have sex with and even care about someone you don't particularly like. There is a difference between 'true love' and 'sex' (even good sex) and they don't necessarily go together.
NC-17 Fics of mine teenagers probably shouldn't read:I have a few other stories rated NC-17/R that I would definitely not advise for an immature audience:
Beg Me For It;
Sex, Drugs and Death Eater Rock;
Not My Affair;
Ante Up!;
Little Boy Blue. These deal with actions that require a little maturity to handle, such as patricide, war, drug use, rape, incest, child molestation.
NC-17 unredeeming porn, go ahead and read:Meanwhile,
Zen Taxi,
Animagick and
Unexpected Guest are strictly porn (and in the case of Animagick, slapstick) with no moral issues one way or the other. If I were a parent I would let my teenagers read them.
R-rated Fics about questionable situations, parental consent first:I'd be more concerned about the issue of prostitution in the R-rated
A Moment Of Sin and Sirius' irresponsibility in the R-rated
A '57 Vincent And A Red-Headed Boy.
My mother, who turns 60 next month, would agree with me.