Yoshine-san came to our department. She's beautiful, kind, and above all, she has a big bust and a glamorous body! However, this is the workplace, so my boss and I suppress our lewd feelings and gaze upon her every day. But there's a rumor that's bothering us... She's a big fan of anal sex, and even when she comes to work, she takes a mysterious pouch to the bathroom every day and apparently does anal masturbation?! To investigate the rumor, my boss and I follow Yoshine-san to the bathroom, but...