I Don't Know, Yoshida Vol. 1

A sexy manga about two college students and the intimate relationship they share in secret. From the author of Lust Geass and Neon Genesis Evangelion: The Shinji Ikari Raising Project!

On the surface, college student Tsukumo Yamada seems to be an average young man just trying to make it through his classes. He seems focused on his studies and not on the gorgeous “mermaid princess,” Mao Yoshida, that walks the campus, garnering the attention of every college boy. But with a subtle glance, their eyes meet for a moment of shared understandings. Moments later, the two are pressed up against each other, bodies hot, breath heavy. Secret meetings, nights spent in exhausting ecstasy, Yamada is actually in an intimate relationship with Yoshida. While they meetup constantly and more than enjoy each other’s company, Yamada is unsure where he stands with Yoshida. Beyond her cool personality and expressionless face, Yoshida becomes a completely different person the moment she’s turned on. Her personality becomes much more dominant, even a touch sadistic, and she can’t be stopped until Yamada fully satisfies her. 

Is this just a friends with benefits situation or could Yamada actually have a future with the beauty everyone desires?