oh goodness me yes. Thank you for this nice little prompt sweetie~
You just know Minho would be a menace with it. Even vampire senses aside he is just so observant, so obviously he notices all the little tells in Jisung. The way he gulps when Minho lets out a random moan because he cracked his neck just right, or the way Jisung clenches his thighs when Minho teases him about being small and cute.
What really turns things around is when one day Minho jump-scares Jisung, coming at him from behind and holding him in a bear hug. That's when he notices. Jisung's heart rabbits and it unlocks something in Minho. He can't help himself from running his nose along the artery running up the human's neck, his vampire instincts taking over, sensing the warm, pulsing blood running just beneath his skin. Not yet he tells himself, wanting to ease the boy into Minho's, erm... condition.
But from then on, something within Minho seeks to make Jisung's heart beat a little faster, blood rush a little quicker, a little warmer. Minho tells himself it's just because he enjoys making Jisung squirm, he is so cute when he acts like a small defenceless animal. But Minho's fangs ache, piercing at the inside of his mouth. The sight makes his dead stomach clench with desire. He can lie to himself all he wants, but he know it's only a matter of time until his instincts get the better of him.
And then.
How will Jisung react?
Will he welcome all of Minho still? Will he be scared, disgusted? The thought of that possibility makes something ugly stir inside Minho - If he doesn't want me then, I will make sure he can never leave me.

Minho tries not to think about the ugly beast inside himself while Jisung dissolves into laughter in his arms -- heartbeat jumping, quickening, heart shaped smile and sparkly boba eyes looking up at the man he doesn't know can end or change his life in the span of a minute.

I-- I just know there is a pwp perv minsung idea in this.

Jisung who knows he is hot shit, used to being lusted over, looked at, even in public toilets. Who develops the habit of picking up men in club bathrooms -- "what, you want to hold it?" he smirks when men not-so-subtly oggle his cock at the urinal.
A quick stall fuck here, wet mouth that is just a hole to be used there. He likes the attention, pathetic men tripping over themselves for a chance.
And then, the day that all changes. The one night Jisung meets Minho.
Minho goes to take a piss next to the urinal Jisung is using, and he is a new face -- Jisung hasn't seen him at this club before. His gaze lingers over the man's beautiful face, down his veiny forearms, his huge cock -- oh
"What?" Minho asks then, "Never seen cock before baby?" It's belittling, voice dripping with arrogance. "Or at least not one as big as mine by the looks of it" He smirks, looking at Jisung's average length.
The tone stirs something in Jisung. He takes Minho by the collar of his shirt.

"Bet you $200 I can make you come like you never did before, pretty boy"
Minho smiles something dangerous.
"Such a roundabout way of asking me to fuck you, sweetheart. You're on."