Bokura no Issen

Sakura Shiba (22 years old) was walking home in a drunken state when he was helped by a much younger boy named Ageha Onaga. In his drunken stupor, Sakura kisses Ageha and drunkenly agrees to a relationship with the boy as a form of "taking responsibility." Sakura is tormented by guilt afterwards and tries to run away, but both parties aren't really willing to let the other one go.

(Source: Fusion Product, translated)