I eavesdrop on my stepsister having sex with her instructor

I found myself eavesdropping on my stepsister's phone conversation, revealing a scandalous secret. It turns out she's been seeing her gym instructor, and he was coming over later that day. I decided to sneak around and catch them in the act. As I waited, I set up a hidden camera in the living room, hoping to capture the steamy encounter. When the time came, I hid upstairs, waiting to see what would unfold. Soon, I heard the door open and their voices grow more intimate. I peeked through the crack of the door and saw them engaged in passionate sex. The sight was captivating, and I couldn't look away. The instructor took her from behind, filling her with his hot load. The scene was pure ecstasy, and I found myself regretting not having a girlfriend myself. This was a wild ride I'll never forget.