Hinamatsuri

A booklet packaged with Fellows! volume 22 at select stores. It's relay manga (each mangaka draws a few panels, and the next mangaka continues the story) from Fellows! collaborators. Originally published in 2012 volume 3 of Gessan, this plus version includes extended commentary by each of the involved creators and a highlight commentary by Satoshi Fukushima who oversaw the manuscripts.

(Source: Natalie, translated)