Remembered a concept I came up with as a horny breast obsessed ttrpg nerd; VtM bloodline of all female vampires that store vitae in their breasts.
So you have vampires able to overfeed as much as they want so long as they can manage their increasingly swollen bust. And of course given the Beast's encouragement, prone to pushing past that point.
You lose yourself in the moment and mass feed in the VIP room at a night club, coming back to yourself with a roomful of people nearly passed out from blood loss and a pair of knockers over a metre across each.
It's thrilling at first, your hands roving over your huge bust - the bits you can still reach anyway - while high off your... well, off your tits, on the rush of vitae and the sensitivity of your monster mammaries. Eventually you come to your senses enough to have to manage the practicalities. While unbelievably hot, a truly titanic rack like that probably constitutes a Masquerade breach, so you've now got to get back to our Haven.
Here's the catch, actually doing so is going to be really difficult, probably impossible without tapping into your disciplines, and doing that requires draining some of the glut of vitae in your oversized rack. Not much, just a little each time, but every time you do you can feel them shrink.
First, you need to boost your strength enough to carry them. Then you need to dominate someone's mind enough to get you something to cover them. Honestly, you probably need to dominate a lot of minds, even if it's just to make them forget what they've seen that night.
By the time you've squeezed yourself into the back seat of a taxi (after dominating the driver naturally) your glorious bounty has diminished to beach ball size. You know you're still huge by any reasonable measure, but the feeling of loss is so profound. You cradle your breasts in your arms, taking in every inch of their swollen size and the sensations of your taut skin, committing it to memory as you know in your heart that they won't last.
It's quicker than you think though.
As you squeeze your immensity through the door to our Haven and I'm waiting for you. Your sire, awoken and naked. My tits are big and fat and full, almost big enough to impede my movement, but you have had the temerity to outgrow me. You actually try to fight me on this, emboldened by being the bigger girl for once. You earned these breasts! I don't give a fuck. Your big bust doesn't protect you from dominate.
When I bite you the feeling is ecstatic. It always does. But as I start to drink your ecstasy is mixed with despair as slowly but surely your enormous breasts begin to wilt.
Bloody tears roll down your cheeks as your proud night's work is slowly undone, even as you orgasm at my feeding. You feel your tits deflate, pleading between gasps and moans for me to have mercy, to leave you with something.
I don't quite take it all. You're left with enough chest to fill a bra. I lie back, glutted to immobility, my breasts bloated to a size that makes your earlier excess feel inadequate. I smirk at your obvious envy and grief and direct you to pleasure my new assets. Cowed completely by your feelings of inadequacy, you comply.
Tomorrow night you'll head out again and feed, maybe try to recover your lost pride in another orgy of feasting. Maybe I'll even let you keep those ones when you come home. I do love the feeling of your massive jugs against mine.
Then again, maybe not. The idea of my titflesh filling this room has its own appeal, and you're so much more compliant when you're nearly flat.