Dark Desire

I have a boyfriend but I recently got aroused when watching lesbian porn. It was then I realized that I have a darker side that I crave women attention. But its not any other woman, she is my boyfriend's older sister. She is 10 years older than me and she is in good shape with her frequent gym workout. When I was watching lesbian porn, I cant stop imagine that I am the one having sex with her. I feel confuse and wrong but I cant help but to rub myself to climax everytime. My fantasy scenario is one day when my bf is out of town, I get to stay overnight with her. We have dinner, TV, chat and we got closer to a point that, we are cuddling and almost whispering to each other. Our face is so close that we gave in and we start making out. We feel each other, exchanging saliva, I eat her pussy and we basically down to scissoring, rubbing our clit to clit until both of us hit our climax. Then we cuddle, kissing, and rest for the night. It will be the night I remember forever in my life.