Mitsuki and Shinomiya have left what most people call "normal" behind and are searching for what "good sex" means for them. In their next challenge, they're trying a toy meant for penetration! Meanwhile, Shinomiya's male kohai at work seems to have a crush on Mitsuki, making Shinomiya burst with jealousy. As her boyfriend, it's up to him to set this straight! But...can he even bring himself to talk about his worries?!