My stepsister's spouse frequently engages in infidelity and has sexual intercourse with me during our threesome encounters

My stepsis is like any other girl in college, she loves to have a good time and she loves to party. But there's one thing that sets her apart from the rest, her stepbrother. He's always out screwing around with other girls, leaving my stepsis alone to come home to him. But instead of being mad, she's totally cool with it. In fact, she's kind of into it. So when we're all alone, she lets him come over and bang her. It's kind of weird, but it's also kind of hot. I mean, watching them go at it is one thing, but actually joining in on the action is another level of crazy. But hey, when you're bored as a college kid, you have to find ways to have fun, right? So when he's around, we all get down and dirty together. It's not your typical family threesome, but it's definitely one for the books.