At school, Aiko discovers that all the girls in her circle of friends aside from her have already had their first menstruation. After going home to her room, she reads up on menstruation and in frustration punches herself in the uterus. This seems to "awaken" Maa-chan, Aiko's anthropomorphic vagina, who begins coughing up blood. Maa-chan introduces herself and says that she's been with her ever since birth and from now on she's going to assist in her journey into adulthood. The next day at school Aiko tells her friends that she's now one of the them.


(Source: MU)

Initially, Aiko no Maa-chan was going to be published on Web Comic Zenyon site, but two days after the serialization started on June 29, 2014 and after only the first chapter was made public, the publisher deemed the content of the manga as "possibly unhealthy" to be published in Tokyo (that is, when it was going to be published in a volume format), and announced to cancel and remove it from the site.


This incident created a big stir on the internet, and about two weeks after the withdrawal, once again the first chapter of the series was made public on the site Manga on Web. In order to raise enough funds for the series to finish and publish it in a volume format, a crowdfunding project on FUNDIY started on August 1. It finished on October 15 exceeding its initial goal of 1,000,000￥ with with a total sum of 1,454,270￥.


The volume was published by Kasakura Publishing on April 28, 2015. At first, the series was planned to consists of 11 chapters, but later it turned out there will be a total of 13 chapters.