My girlfriend, her step-sister and I were staying at a hotel in a resort I woke up to be invited into the bathroom by my girlfriend's half-sister when GF was relaxing next to me. I went with a busty brunette and didn't regret it. The beauty allowed me to fuck her mouth and tight pussy, after which I cum twice on her lustful face. We fucked near to my girlfriend and I was insanely turned on by breaking this taboo. My beautiful girlfriend never found out about my betrayal.