Happening Bar de Aimashou

Akira Yotsuya is a hard-working salaryman whose only pleasure is masturbating in front of a mirror in cosplay to simulate "groping play" where others can see him in a lascivious state. One day, Yotsuya gets interested in a happening bar and decides to brave the elements and visit. There, she meets a younger, handsome man named Soma Yamashiro, who is a bit of a sourpuss. He uses verbal abuse to induce her to masturbate, and makes her cum wildly in front of the other customers.

(Source: Ichijinsha, translated)