Unintentionally penetrated and filled with cream by my stepsister instead of my preferred sex toy

I was on my way to my favorite hangout spot when I stumbled upon my stepsister in a compromising position. Unwilling to cause any trouble, I let her continue. Later, she confessed her desire for rough sex and my surprise turned into excitement. We indulged, and she took it like a pro, ending in a satisfying creampie.