Miyu and I stayed behind to prepare for the school festival. There was a rope we had used for work, so I jokingly asked her if I could use it to tie her up. She said "Eh?" with a shy look on her face, but she didn't refuse. I tied her up roughly, but she started moaning and climaxing wildly... I went crazy seeing her lewd face. Driven by the urge to make Miyu, whose masochistic switch had been turned on, do more of what I wanted, I continued to play as I thought of it. It escalated more and more, and she went crazy with the painful and painfully pleasurable SM sex...