First time with a big dick for my step sister's birthday

On the day of my step sister's birthday, I decided to surprise her with a special gift. I had been saving up for a while and finally managed to buy her a big, shiny dildo. I wrapped it up nicely and placed it under the bed, hoping that she wouldn't peek. When she opened her birthday presents, she was delighted to find the dildo. She couldn't wait to try it out and invited me to join her. I had never been with a girl before, let alone one with such big tits, but I was excited to give it a try. As we got comfortable on the couch, she took out the dildo and started to play with it. I could feel my excitement building up as she rubbed it against my cock. When she finally put it in her mouth, I couldn't believe how much pleasure I was feeling. It was my first time with a girl and my first time with a big dick, and I knew I wanted more.