pencil and story: NewMeN

Misses Miki Yamaguchi and Mayumi Hachiya meet in the teacher's lounge.
When Mayumi reveals to her already excited friend that she has a gifted young lover at her disposal, Miki strikes a deal to share him.
In return Mayumi asks Miki to have sex with her right away.
The relationship is very intense, so much so that Mayumi finds herself with a fractured hand after having inserted it into her friend's sex.