ERDM-100 "Ultra Close Call! Will it be found out or not!?" Girlfriend's best friend reverse NTR loses sanity! Sex while holding back moans! 4 hours

Because she said she was bringing her best friend, I tried to act like a good boyfriend. But then that girl turned out to be exactly my type! After hanging out with the three of us for a while, she fell asleep, and it started to feel like a good mood between just me and that girl. I didn't want to get yelled at by her, nor did I want to cause any trouble... As I was agonizing over it, the girl said, 'If you promise to keep it a secret, I'll do it too.' What? Really? We carefully performed the act without making noise next to my sleeping girlfriend.