I'm Not a Succubus! Vol. 4 (manga)

Sakura, a human only pretending to be a succubus at her monster girl high school, finds herself the very center of sapphic attention! Harpy Hayate’s laying period is coming up, and she’s harboring the hope that her crush Sakura will help her with passing her egg! Meanwhile, every body part—including tails, tentacles, and wings!—is fair play during a sweaty game of kick volleyball in the school's gymnasium! When Hayate and Sakura encounter one another in the gym's supply room after the match, anything can happen...but what will?!