Although possible, sex normally does not last for 14 hours. I like tender, emotionally charged sex scenes, with real human attributes. I don't know how many stories I've read where a couple has just met and then proceeded to make love for an entire weekend. Taboo subjects are OK to write about as well, but the same guidelines are worth considering. If you want your writing to be noticed and respected, write respectably.
Good writing begins with re-writing.
Show your work to those whom you know appreciate your genre and listen to their criticism. You don't have to accept the criticism of others, but you just might be able to improve your story, and your writing. Come back often to The International Fiction and Poetry Society and take advantage of workshops, chat forums and an opportunity to read good erotica as well as a wonderful collection of poetry, and fiction of other genre's. The Humor Source Webmasters' Ezine Gothic.