I ended up living with my father's new wife's lewd stepdaughters. My step-sister came home early in the morning, hungover and lying on the sofa, showing off her unprotected panties. I was so excited that I was masturbating in the bath when suddenly my step-sister opened the door and came in, started taking off her clothes and said, "Brother, let's go in together!" She grabbed my rock hard cock from behind and was so excited. I prayed that no one would wake up and made her suck my cock. I pretended to wash her body and touched her lewd parts, and since she was soaking wet, I inserted my cock. My step-sister was so excited that she started crying. I didn't want to get caught, so I had forbidden brother-sister sex in her room.