Kotomi-chan is a member of the vocal music club who has been learning piano since she was a child and loves music. She is a cheerful girl who is always smiling, but her sexual desire is greater than you would imagine... She has a strong masochistic streak, and if she is treated roughly, she feels so much that a stain appears on her panties. And the intense and relentless attack by the male actor makes her climax many times, leaving her face a mess.