Since the day Bram Stoker penned the account of Lucy Westenra being ravaged by Count Dracula; most vampire, and horror fans, have associated our favourite, undead, blood-drinking harbingers with sex or at the very least consider them sexual beings with a lust for flesh which matches their own lust for blood. We see this theme carried strongly over time, though each author's own personal mythos will have an obvious effect on their vampire character's need or desire for sex, but the theme of viewing them as sexual entities seems to remain the same. Vampire Diaries, Twilight, and True Blood (to cite a few contemporary vampire myths) all turn in this direction unabashedly and never seem to look back.
It is one thing to suggest that vampires have an unearthly beauty and grace about them. That mortals would find them attractive due to perhaps their power or ability to manipulate them with their charms or seemingly magical abilities. It is quite another to say one would willingly participate in, what could at the very least, be described as necrophilia. Sure, they walk, they talk, they think, but by and large they are certainly never considered to be ever truly alive. This is poignant in True Blood, where we see a human society bisected by this question. Many are disturbed, if not entirely disgusted by the idea of sleeping with a creature they understand to be dead. Others, although curious and perhaps intrigued by the thought of intercourse with a vampire, are tentative at best in their acceptance of it. The few characters we do see that voluntarily participate in this act, by and large, seem to be directly under the supernatural charms of the nosferatu with minimal exceptions.
Even if this directly answers the questions of a human's sexual response to a vampire, it does little to address the individual vampire's desire for sexual intimacy. In humans and animal's a like, this process is considered a biological imperative, a simple part of the human desire to "mate, feed, kill, repeat." Although the act of intercourse might have pleasurable side effects, for vampires the act of sex in no singular way suits their biological imperative If vampires cannot reproduce (by majority of myths) sexually, would it not theoretically remove the imperative, and therefore the desire to participate in coitus? This is not to say that they would not have sex, a moment may arise for them to have or use sex in order to get what they're really after: blood, it seems that to a vampire, sex would be little more than just a tool. Perhaps even fledgling vampires with recent memories of making love would still attempt the act as they struggle against their new natures, but does this mean they would continue to actively seek it out over time as they aged? What do you think?