What is the theme in Bloodsucking Fiends by Christopher Moore?

Bloodsucking Fiends is about relationships, and no relationship is based purely on love. All of the characters have desires they are trying to fulfill, and they enter into relationships to fulfill their own desires. Jody needs someone to protect her, to keep her safe during the daytime, and to do errands for her that she can't accomplish during the night. Even more than that, she needs some way to fight off loneliness. Jody hates being alone, and she is willing to do almost anything to fight loneliness. Her ultimate act of manipulating Tommy is in turning him into a vampire to fulfill her own needs.