Shinkuu Katakoi Pack

Summary

Sakurai is a high school boy who discovers there's more to teachers–to adults–than what they show to others. After seeing a normally poker-faced teacher skip lively down the street in the rain, he can't get her out of his mind. When he asks her what would happen if he liked her and wanted her to go out with him, he gets a surprising answer. from:Manga Habit Blog