Haneru Kimi wo Tomeru Boku

Riko Makabe and Kohei Kiyotsuka studied calligraphy together as children. At that time, Riko fell in love with Kohei after a playful encounter that awakened her sexual fetish. When they meet again at university, they become lovers, but they are unable to cross the line because of Kohei's insistence for a pure and proper relationship. This is a campus romantic comedy about the push-and-pull between an aggressive girl and her honest younger boyfriend!

(Source: Comic Jardin, translated)