A crossover chapter between the Ijiranaide, Nagatoro-san and Magical Sempai manga series. The chapter was released in both Magazine Pocket and Weekly Young Magazine, then later reprinted in the second Illust Collection of Ijiranaide, Nagatoro-san. The twelfth page is different between the two original releases, with Magazine Pocket's and Weekly Young Magazine's versions focusing on Nagatoro and Magical Sempai respectively; the Illust Collection version contains both pages.

(Source: Nagatoro Wikia, edited)