I love the idea of the Ventrue feeding "preference" not always being a preference in the sense of the Ventrue having an unqualified attraction to that type of vessel. In fact, it could be a type that the vampire has actual (physical or social) distaste for. Have a homophobic male Ventrue who can only feed from men--or, even worse--only from homosexual men. Or an upper-class character who can only feed from homeless people; or a passionate union boss from the '30's who can only feed from rich corporate types. Or a Ventrue with high Humanity who can only feed on children--how's that for angst? You could also make the vessel something that, in life, inspired complex love/hate feelings in the character, a la Frollo and Esmeralda in *Notre-Dame de Paris.*
Hey, it's a heck of a lot more interesting than your usual aristocratic Blue-Blood whose feeding restriction is "nubile young virgins, of COURSE." The Ventrue feeding restriction is an excellent opportunity to challenge the character, emotionally or logistically. I say, take it. :-)
As for the sexuality of feeding in general, I personally have it vary from vampire to vampire, depending on what maks for interesting character dynamics and what the character's philosophical attitude toward vampirism is. Those with high Humanity who choose to go the Casanova route are likely, at least at first, to choose vessels that they would have been sexually attracted to in life (though I think it's entirely likely that elders would generally have much broader and more exotic tastes...boredom being deadly to the soul and all). On the other hand, they're probably much more likely to feel guilt over being "supernatural whores." However, becoming a vampire might also give a character an excuse to begin choosing erotic partners that she could never have even considered being intimate with in life. For instance, you could have a vampire who always suppressed her attraction to men of another race because of the social stigma...but once she's undead and thus theoretically unbeholden to the standards of her society, she starts accommodating this taste. Or a rather homely vampire who immediately begins putting his ability to force supermodels to his will to his own advantage. (Which of course, the ST has a bounden duty to use as a trap to lure the character into BIG trouble. :-)
In a story, I like to throw vampires with radically different attitudes toward feeding together for drama purposes. For instance, my Tremere character, as an apprentice in Renaissance Florence, is used to treating feeding as an intimate, very sexualized, and naturally very, VERY sinful act. His compadres in this particular chantry, however, regard feeding as an uninspiring but necessary and tolerable interruption to their studies (after all, they're coming from a mage-ly perspective where blood is simply the substitute for the old potions of longevity), which they want to accomplish with as little fuss as possible. This makes for some wonderful conflicts.
After all, RL people have all sorts of varying attitudes toward sex itself. It seems to me totally natural that vampires would have a whole spectrum of attitudes toward feeding and its inherent sexuality (if any). And that will make for more interesting games, since the players won't be able to assume things about other characters.
A final remark: I personally tend to give many vampire characters, particularly elders, at least a hint of sadomasochism. First of all, the vampire myth, in its most alluring, neo-Gothic (19c.) form, is already inherently sadistic. "I've got you in my power. I can kill you if I want. In fact, I will kill you and you're going to love every second of it. In fact, why don't I take a whole week to slowly drain you, forcing you to come whenever I beckon. I will corrupt you right out of your repressed Victorian sexuality and make you enter my dark demimonde of licentiousness. Forever." Ooh, hurt me. :-)
It is also my (not terribly expert) understanding that very often the RL people who most ardently long for and pursue submission and humiliation under a domina/dominus are people who are very powerful in their everyday life: politicians, Wall Street brokers, CEOs, etc. When I first heard that, it inspired me to start seeing many elders as creatures who feel trapped in their own power, and who thus secretly get a frisson of paranoid excitement whenever they're made vulnerable...while feeding, for instance, or when challenged from an unexpected quarter. ("Well! You seem to have the advantage, for the moment. I had not expected such spirit..." YOU know.) So there's the masochistic half of the equation.
At the same time, power is all most elders have left, and so their chief pleasure in unlife is exercising it. And that's the sadistic half. Since mortals, who are largely helpless against vampires, are particularly easy to dominate, feeding becomes a natural staging ground for little games of seduction/hunting/whatever. (Non-consensual games, usually, but hey, nobody said vampires are all nice guys.) However, it's more challenging, and thus more rewarding, to gain dominance over other vampires. (Feeding on another vampire would, of course, be the highest and most intimate expression of this dominance; and as a bonus, it may even have the added spark of risk--of the Blood Bond.) Plotting to overthrow other Kindred is not just a mental exercise for some elders, something to kill time; it is the one erotic thrill they can still truly enjoy, abstract as it may seem to the living. I would be willing to bet good money that the most intense rivalries of the Jyhad are very erotic in nature, whether or not the participants themselves have an actual physical relationship or even see their struggle in those terms.
Sarah Roark, author.