Have you Visited the Tall Vampire Lady under the Manor? Or Edith, for short.
Ask Pixie, about her and she will give you "Do what you want" ticket. Go to the Basement, and Bam.
Ensure that you Bring Rinny, along for this or you can't do anything to Edith.
Make Rinny, do the spell on her and she will gladly teach it afterwards.