Story Writing Discussion

A small issue seems to have come up with the story I linked in "Hello, Everyone!"   Its description seems to have been a little vague in one of the forums it is posted in, and the reviewer was not aware that he was reading erotica. The truly erotic scene is at the end of the story. It is one with a, "the hero gets the girl," type ending. It does have clues throughout the story that it is a bit "kinky."

My question is, how can I clue in the reader at the start of the story, that it is erotica, without giving too much away?

Light
Science, Science Fiction/Fantasy, Metaphysical