After Midnight Skin

The hidden secret of the serious office worker Toraya is that he has a strong sexual desire. He's always looking for the perfect guy for him, although lately he's been working hard and hasn't gotten any sex at all. One day after a long day of hard work, he's masturbating in the office's toilet because of the stress of working overtime. But he accidentally gets caught by his boss Saikawa...!?

(Source: Hakusensha, translated)