You explain that since when vampire bites a human it turns that human into a vampire, then obviously a human biting a vampire will turn the vampire into a human. Swayed by your ironclad logic, and rather bored of being here instead of partying, the vampire agrees to give it a shot. And would you look at that, it works. One meaty chomp later the vampire is right back to being human, completely devastating the entire literary metaphor that vampires are supposed to represent. Social taboo on vampires going to parties without a second vampire successfully bypassed, the now ex-vampire grabs their gear and heads back to your camp party, where they proceed to rock an amazing underground set.