If there's one thing we've learned after 5+ seasons of True Blood, it's that men's buttocks are the new side-boob. But if there are two things, it's that vampires take the bonds of blood very seriously. Eric Northman believes Godric is God; his maker exercises more influence over him than the actual vampire goddess, Lilith, despite Lilith being older, taller, and far more naked. Pam's devotion to Eric is absolute, even though, like many fathers of daughters, he'd rather self-immolate than listen to her girl problems. Bill and Jessica play out like single dad and rebellious teenager, with draining humans subbed in for draining Boone's Farm on the list of infractions that merit an awkward lecture.
All of which begs the question: in this world of incest-happy TV, are hyper-sexual vampires cool with diddling their relations? You'd think that, given their callous disregard for human morality, these toothy beasts would feel no compunction about forming the beast with two backs with their vamp children, parents, and siblings. There's no biological reason against it, what with their wombs being as vestigial as our appendixes. But there do seem to be rules, or at least guidelines.
For starters, responsible male vampires do not have sex with their daughters. Even after turning into a shrieking puddle of ancient blood and nearly pulling Jessica's heart out of her chest, Bill's first instinct in the bedroom is to tuck her in and say nighty night. Of course Jessica is a child, for whom Bill bears full responsibility for making, and at least for this century that eliminates his temptation*. But what about Eric and Pam? Even when Northman went full Viking on Human Swynford De Beaufort, his interest seemed more protective than sexual. Once he turned her, it became purely paternal, and their sexual history became a wedge in the new relationship. The lesson: don't make a woman into your vampire daughter just because you slept with her, and feel that you owe her something. Do it because you see budding leadership qualities that could make her a future Magister, or even Chancellor of the Authority.