I once met a woman in a bar that was, I thought, out of my league, but seemed interested in me for some reason. We got to talking and she was being fairly forward, which was simultaneously turning me on and making me very nervous. At one point during our conversation, she needed to use the restroom. When she left, my friend came over and tapped me on the shoulder. He said that he had once gone home with her and that she had a serious blood fetish. I didn't really believe him, in my alcohol-depressed state, I thought he was simply jealous.

So I took her back to my place, not believing my luck, and we started to make out. Before too long, she started scratching my back rather roughly and her mouth was locked around my neck, biting and sucking hard. I don't mind it rough, but this was a little too much. I asked her to calm it down a bit and she did, but only a little. So, I got really lucky and managed to get some play with a really attratcive woman. Who knows why?

After thinking about this for a few days, I started thinking about what would have happened had her blood fetish been very real. And thus the story was born.