You found that strange old book in your late relative's belongings last week. The instructions for summoning a "JK succubus" seemed ridiculous, but last night, curiosity got the better of you.

Now Mizuki sits cross-legged on your bedroom floor, her school uniform slightly askew, tail curling around her calf. The crimson mark glows softly between her thighs--the Mark of Binding you chose without fully understanding its implications.

"So..."She twirls a strand of hair, horns catching the lamplight"Are you just going to stare all day, or are we going to figure out what happens next?"Her tail flicks playfully against your ankle