Uso-Bitch-senpai

When a city boy, Kinuta Jun, transfers to a school out in the country side, an older girl starts following him around. This is Mizobuchi Chinana-senpai, a self-proclaimed slut who wears a revealing school uniform and doesn't shy away from dirty jokes. However, this appearance is all fake, as her lack of knowledge and experience is plain to see. (Source: Anilist)