A single OVA comedy with ecchi, romance and supernatural elements, released alongside the limited edition of the manga's seventh volume. The episode is billed as exclusive, forbidden material that cannot be shown on television. It comes in two segments. In the first, Torii Shoutarou tails his younger sister while she is out on a date. In the second, Mitsuki, Yuuya and their friends spend Christmas Eve together at Kanzaki's house.