Hoteru Watashi ni Koi wo Oshiete

Miku is a high school girl who likes to fantasize about boys but has no real experience with them. At school, she acts like a pure, good girl, but one day her childhood friend, Shida, finds out that she's been reading erotic manga! She thought that her life was over… but then Shida-kun asks her, "Would you like to gain some experience with a guy...?" It's a romantic comedy between a girl full of romantic daydreams and a mischievous boy who likes to tease, set in a public bathhouse!

(Source: Kodansha, translated)