[DVAJ-686] I'm a gloomy guy who is made to watch over a bad couple having sex at school, but after the fact, a girl who is not satisfied with her premature ejaculation boyfriend secretly invites me to be a substitute dick and I spend my days fucking an (Censored)

I'm a virgin and a bullied boy who was ordered to keep watch over a bad couple who were having sex at school instead of a love hotel. I couldn't resist and looked in, and my eyes met hers! Oh no, I've been found out... but after the fact, she called me and said, "You were looking just now, weren't you?" and "Show me your dick too," leading to an unexpected development. It seems that her boyfriend was frustrated with his lack of premature ejaculation techniques, and he was very interested in my rock-hard dick. Pushed by the momentum, we had a great chemistry and he came over and over again, and she was addicted to the orgasm she had never experienced before. From then on, I started secretly having sex with her after keeping an eye on her.