“Bite me” splashes across the chest of a 13-year-old waiting in line in San Francisco to meet the cast of Twilight. “Bloodsuckers Anonymous” proclaims another shirt. One of the more clever reads: “I didn’t get into Hogwarts, so I’m moving to Forks to live with the Cullens” (then again, who doesn’t get into Hogwarts?). Not since Buffy slayed her last vampire in 2003 has biting lore taken on such a titillating tone. With the advent of movies like Twilight and TV shows like True Blood, the main question on everyone’s mind is: where’s the nearest Red Cross and how much for a pint?

Vampires attracted mortals long before Dracula got his hands (or teeth) on a few newlyweds. Though various cultures continually reinvent them (think Babylonian Lilith or the Malaysian Penanggalan), modern Western media has them pegged as (un)deathly pale, eternally handsome and infinitely virile.

Alan Ball’s HBO series True Blood capitalizes on this potency. The interaction between Sookie Stackhouse (Anna Paquin) and vampire Bill Compton (the divinely British Stephen Moyer) is tantamount to series-long foreplay, teasing but somehow satisfying. They eventually consummate their love — a bite and squirt of blood function as the archetypal apple — and make the rest of us wonder, what is it about vampires that causes so much delirium?

The idea of something being both dangerous and pleasure-inducing underlines most addictions, and mingling with vampires is no exception. Even the reluctant chastity of Twilight’s Bella Swan speaks to the hormonal reserves pining for release in Edward’s marble-cold arms.

Societal obsession with vampires also hinges on entrancement with the unknown. Vampires know the secret to immortality, one that blends the past and present in a way humans cannot understand. Reflections on their past lives are sometimes more fascinating than their penchant for blood-lapping. For a society that’s hell-bent on understanding the roots of why things happen, vampires possess a sagacity no grad school can offer. The quest for knowledge, alongside the quest for sexual gratification, is a combination that's hard to resist.

Sex and blood will always captivate American audiences, but this particular congealment resonates deeply. Sin and pleasure coursing through societal arteries makes it a ripe time for vampires’ return. And despite J.K. Rowling, a bite mark is much sexier than the Dark Mark.