I didn't mean "fantasizing" as in "desire" but as in, thinking of it the way you'd dream up other stories.
It's a writer's job to sink himself deep into things that "normal" people don't like, or fear, in order to tell the truth about it. Nabokov spent quite a bit of time writing Lolita, but it doesn't mean he was a pedophile. Writing about a serial killer doesn't make you one, or wish to be one. Getting defensive about the subject of your writing isn't necessary. A writer should be able to write about anything and not be thought the worse for it. Otherwise, writers would confine their work to puppies and kittens and knitting, as someone said earlier in this thread. Do we condemn an actor for playing Hitler in a movie? Do we condemn Anthony Hopkins for playing cannibalistic serial killer Hannibal Lecter? Of course not.
you're agonizing over nothing... stuff like that is written about all the time, so i have a hard time believing that an adult your age would even worry about it at all... you must not be well-read in the horror/vampire/erotica genres... go ahead and include it, if you feel it's necessary... if it works for the story and the writing is good enough, i doubt any publisher will give a hoot... and if they want the ms with that taken out, they'll tell you...