After centuries of the Belmont clan whipping him into submission, Dracula found himself looking forward to the slayer family's regular visits.
What does Dracula have to do besides being whipped? He's either trapped in another dimension for hundreds of years between video games or worse, dead, waiting to be resurrected and killed all over again. Eventually the guy is going to start craving human companionship on top of human blood, and when it comes right down to it, getting whipped by a strapping adventurer is a form of social interaction.
The safe word is a little creepy though.