Perhaps it was. Vampires have a hypnotic sensuality. When someone we have set our sights on is close enough, it is almost like a spell itself.
An example... normally my bite does not turn a person. I never take so much that it kills them. And almost all that I take is in such the throes of passion that the person I am sipping from doesn't know it and it simply intensifies their climax.
I have only taken offered blood from someone for another reason once. And she did it to save my life.