I'm Not a Succubus! manga volume 2 features story and art by Horitomo.

The timid but beautiful Sakura spends her school days pretending to be a succubus, and living in fear that her monster girl classmates will discover her secret—that she’s a mere human! Whether it’s helping her centaur classmate Chisato with a sacred archery ritual and then getting in some bareback riding practice, or helping a horny harpy lay an egg, Sakura has to be the hands-on ever-ready sex demon, or her days at the academy could be numbered!