Sexually-charged or erotic horror lurks with its brethren among the thousand offspring of the horror genre, that monster umbrella that gives us everything from slasher’s teenage morality to torture porn’s revolting screams and arterial sprays. All in all horror is the most diversely subgenrefied (and among the most studied) categories of fiction. And among the least commonly used subgenres within it is erotic horror, because it’s hard hard hard to do. So we’ll have to …