I don’t think I quite built this up as much as you described but I hope you enjoy it nonetheless!

Tsukishima, on
the whole, is not overly fond of his species. It’s downright tiring to need sex
of all things to survive. He knows pretty much all males would disagree but
they don’t have to deal with this! That and since he’d prefer not leaving a body count, thank you very
much, he has to expend more energy in either wiping his conquests memories or
deal with having a reputation of being a player. Which means garnering new
sources of energy is that much more work and he has to use more power to seduce
them.

It’s a vicious
cycle really.

Which is why,
when he meets you, and genuinely feels
something, he thinks he’s home free. It’s not every day incubi mate but it’s
not unheard of.

Except that nothing he tries works on you; not his
normal flirting (honed by years and years of practice), not even his powers of
suggestion or hypnotism. At best, he’s managed to gain you as somewhat of a
friend, which is worse because your proximity is driving him crazy. And the
constant teasing from his fellow incubi is not
helping.

Just when he’s
ready to throw in the towel and find some random girl to screw, you enter your
room, unware he’s there. He’d come over to ask for your study notes, waiting as
instructed by your mother for your return from taking a shower. When your eyes
land on him, it’s like a veil has been lifted.

“Kei,” you
breathe and his own breath hitches when you let the towel fall. You’re fucking
gorgeous.

“Wha-“ he
begins then realizes; you aren’t wearing anything, which means the necklace you
always wear is sitting on your desk. Of course! A warding charm!

Deciding to
save disposal of it for another time, Kei is on you in a second, lips crashing
into yours, tongue dominating your mouth easily. He shucks his clothing,
groaning under the ministrations of your fingers against tight muscle and
oversensitive skin. His body is practically humming with need and he knows if
he doesn’t slow down, isn’t careful, he’ll drain you dry.

“Please,” you
gasp, legs parting for his body to lie flush to yours. He doesn’t even remember
carrying you to the bed.

He can’t wait,
only hoping somehow his over exertion of pheromones have allowed your body to
be ready. He thrusts in and out rapidly, power surging through his veins. He
kisses you, stealing your breath, making you sweat, trailing fingers through
damp hair which he clutches and pulls. When he looks in your eyes his own are
blown wide, the gold bright and glowing. “You know what I am now,” he affirms
and you nod. “Will you let me mate you? Will you be my source of energy
forever?” When you nod again, his mouth is on your neck, sucking hard before he
bites. He explodes within you, his scent flooding over you like a blanket
indicating you are his and if any
other incubi so much as look in your direction with intent to take, he’ll kill
them.

While you’re
asleep, he rises, taking the necklace and crushing it.

You have no
need for warding anymore.