Oogami-san, Dadamore desu.

Ogami-san has been keeping a dirty little secret from her peers at school: Puberty has emptied her mind of everything but perverted fantasies! For the sake of leading an ordinary school life, she pulls out all the stops to keep her mental wild side under wraps. But when she literally reaches a hand out to Yaginuma-kun, a cute but mysterious boy in her class, her innermost thoughts just come spilling out! All she wants is to get to know him (and his body) better, but she can’t do that without the risk of exposing her true self. What’s a girl to do?!

(Source: Kodansha USA)