Well written erotic fiction will get your members cumming.
Depending on how you FORMAT the stories is also important in getting the maximum benefit from a story or set of stories.
If you have several sets of photographs, add a story with the gallery.
Let the pictures give them the visual.
Let the story make them want more.

Give your customers a chance to dream.
Words help make the fantasy more real.
Exclusive stories gives your members a bit extra, that they don't get everywhere.