Not to potentially derail the discussion but I've had this stuck in my head since yesterday so just bear with my autism.
Did YOU know that VTM vampires canonically have an ability to get their dick hard(Amidst other things)?
It costs a single blood point for the duration of the scene, presumed to be a single orgasm in this instance. This means that your average 9th generation vampire can orgasm fourteen times total. Not that it will be an easy ordeal for them. Vitae is required for a vampire to function in nearly all aspects. A vampire low on blood will be weaker, they will heal slower, they will have reduced mental faculties, etc. it's SO important in fact that when a vampire gets too hungry they literally lose their mind and succumb to a bestial frenzy until they're fed again.
Put all this together and it means that you're not just milking a vampire for their cummies, You're milking both their blood AND their sanity as well! Every orgasm pushes them ever closer to the edge and they'll be able to FEEL it. They'll KNOW what's coming, they'll have that howling in their ears even as their thighs tremble and balls clench.
As a further fun fact, did YOU know that werewolf blood is exceptionally nourishing for a vampire? With the small, small caveat that every time it's consumed their ability to resist frenzy is reduced. Meaning, hypothetically, they could be yo-yo'd back and forth between madness and euphoria with every crash against their hips.
Thank you for for participating in my involuntary ted talk on how to train your vampire.