As you know, Krowly can leave Lizzy at home if you want. 
And if she will stay hungry for three days it will start the secret quest.

Talk to Carla about the rumors and she will say that the men of the village 
looks tired recently, and she is worrying about a vampire.

And if Krowly will explore the houses in the village at night he could find that it's not a vampire..

Hungry Lizzy's visiting Eric, Derek, Sebastian and Old man Jason in the different days of the weeks. 
You can't see her sucking Sebastian's dick, but he will mention next day that he had a weird dream. 
(Yep, we all remember that awesome comic about the spider by Oglaf  :D )

The quest ends here but the scenes will be repeating every time LIzzy stays hungry long enough. 
I thought small elements like this will help to bring more life to the village :)