pmmg
Myth Weaver
lol. Ewwwwwwww, gross. Cover your eyes.
But wait, I looked...
I don't know, I believe in giving the story what it needs. If sex needs to be in there, than by all means...put it in. If not, then I would leave it out. Like everything else, one has to ask what this is really adding to the story. If its adding something important then in it has to go. I think it mostly belongs if it adds to understanding the characters, being witness to the ways in which they grow or relate, or culminates something that has been building for a long time, or I suppose adds to the tone of the story.
In addressing the original post, sounds like something with a soft R rating would most likely suit. Though, you really should not write with the fear that others may read it. You gotta write it the way it needs to be. Dance like no one is watching, and all that.