I've been keeping a sex doll as a secret from my sister. It's been my little pleasure toy that I use when I'm alone. One day, I caught her using it while I was away. She was so naughty, pleasuring herself with my toy. I watched as she took it in her mouth, her hands, and even her pussy. She was so eager to please herself, just like how I would use it. I couldn't help but get turned on watching her. So, I joined in and we had a wild time fucking that doll together. We took turns sucking it, riding it, and getting fucked by it. The sight of her big tits bouncing as she rode that doll was just too much for me to handle. We went at it hard and fast, our bodies entwined in a steamy session of sex. In the end, we both were left panting and satisfied, covered in each other's sweat and cum. What a naughty little sis!.