I have this theory that Madotsuki is a murder victim.
Perhaps all the women in her dreams are the murder victims, Monoko and Monoe her closest friends.
Of course, Masada was her piano teacher who also fell victim to the murder.
Perhaps Poniko is the murderer, since she turns into Uboa, she maybe snapped one day and killed everyone, hence Uboa.
Perhaps Kyu-Kyu-kun, and the "face" that follows it might represent her seeing her friends getting killed(and maybe raped, since Kyu-kyu-kun looks slightly like a penis) by Poniko, who is really a boy, but an innocent girl, maybe saying he looked inncoent, but soon turned into a monster(Uboa).
And her killing herself at the end, maybe that's her finally coming to terms that she is really dead?
The Toriningen are maybe there to represent "gangbangers" that helped Poniko kill her?