Chintsubuちんつぶ; Chinko no Tsubuyaki; Murmur of a Penis

Toride has always loved his cute classmate, Ayase. Due to an accident, Toride's spirit went to Ayase's penis, a weird couple then was made. They both have feelings for each other, but is it really a blissful thing for a relationship such as this? The accident not only changed Toride and Ayase's life, but also Iwabuchi- the emotionless, and Kamiya- the playboy? Unlike Toride and Ayase's situation, Iwabuchi and Kamiya have their penis switched, and their penis can talk?