These stories use magic to . . . enhance the mood. This may mean something as simple as magical sex toys, or it may mean the use of magic to fundamentally alter the experience of sexuality.
Quill and Ink Read review here (note: this is a sequel to the delightful "Something to Write On," and will make more sense if you read that story first. The link is to the author's home page; click through to get story title link)
Nym, Sins of Omission (note: link is to the author's home page. Click on "Fan fiction" and then scroll down the page. This is actually an incomplete series of stories, but is still well worth reading.)