Menchi Kitte, Koi.

"I'll pay for the coffee, so let me draw for you!" Manga artist Isaki calls out to the tough-looking ex-delinquent Hiyotaka. He immediately poses for his drawing, and although he thought they would never meet again, a relationship begins between the two when Isaki forgets something. The two are uneven, but they color each other's lives. (Source: Kadokawa, translated)