I mean FOR ME it's the moment just after my fangs have sunk all the way in and that which I crave has started to flow in to me. It's pretty damn pleasurable to me too! You could probably argue that what makes me a magical creature likely wants to reinforce I do the things to keep it moving!

As for the prey, well if we like you then we'll obviously ensure you're adequately tranced, feeling very good and to make sure (and reinforce) how much pleasure every bit of suction, hearing every gulp, your biter takes will give you. We could even make sure that it surpasses other pleasures~