Could the Admired 20cm 'Giant' on Secret Social Media Be Surprisingly Close? If I'm Pierced by Something That Big... What Will Become of Me!?

Do you really think I can let you go? You found out my secret, didn't you? Kayano was dating her coworker, Shunpei, for three years, even considering marriage, until he cheated on her after she faked satisfaction in bed. Comforted by the sexy images and videos of an anonymous SNS user named Shirotaman, she continues her job. One day, during an overtime dinner with her boss, Mashiro, she notices the scars on his hand, realizing he's Shirotaman...?