My sister is searching for a book she and I had read in our teens (around 1988/89). It was about these two teenage girls who were either hitchiking or just walking down the road, may have been coming from school. I want to say they were blonds. This car picks them up and takes them to this place where they are stripped and hung by their hands, while their blood slowly drips out of them. The blood is used to keep a witch/warlock young. The one girls manages to escape if I remember correctly.  The whole story was very cliche. The premise was that in order for the witch/warlock to stay young they had to drink the blood of virgins.

Does anyone recognize the story and maybe know the name?

Thanks.