Is not a doujinshi of another manga, is a spin-off of Kami-sama No Ude No Naka. It was made for a big doujinshis event that took place in Japan twice a year. Nekota sensei was working in Hidoku Shinaide the last few events and because of that there are a big gap between the last chapter of Michiru Heya . I hope you could understand me, english is not my first language.
Only Nekota sensei knows...
But it seems she is bored, it costs too many time finish it.
But it is a doujinshi of what manga?