Aiko no Maa-chan

Aiko notices that her female classmates have all experienced their first menstruation, while she has not. After researching the topic at home, she impulsively strikes her own body in frustration. This action appears to awaken Maa-chan, a personified representation of Aiko's vagina, who begins coughing blood and introduces herself. Maa-chan claims to have been with Aiko since birth and states she will help guide her through adulthood. The following day at school, Aiko announces to her friends that she is now one of them.