She faced mark kissing him as Milton pressed his cock against her ass and kissed the back of her neck. It was so hot. she kissed her way down to his c...ock. I watched as she began sucking his cock. Things were happening fast now. Mark had his fingers in her pussy and she was close to her first cum of the night. She switched cocks and as she was sucking Mark Milton started rubbing his cock up and down her pussy. She mad motions to get him in but for over 10 minutes all he did was get the head of. I was in full excitement to do something and taken some steps too. I touched her palms and hold it for long time whenever possible. She never mistaken me or stepped away from me.I try to hug her but stopped a little bit to express. She was a mystery to me in all different parts of my life with some clues to fill. As i spoke about lecture of class she was tensed to change topic and talk about personal stuff.I always was day dreaming about her.Her image is placed in my dreams.She was a curious. After a couple minutes of slowly sliding in till I felt resistance, then pulling all the way out with a 'pop', I was finally hilt deep in my little sister's pussy. I stood still for a moment, just enjoying the feeling of being fully wrapped within her.She looked at me through the mirror, and smiled. "You fill me up rather nicely big brother." She wiggled her ass, and I couldn't stop a moan of pleasure from escaping my lips. I began to move my hips, slipping in and out of Lisa's sucking pussy,. "Hi," he said, then looking at his chart. "Hi, Lisa!" He didn't remember me from the last time, but I certainly did. Dr.Phillip had an easy way and the way he looked and touched during an exam always made me wet, even though I don't think he knew the effect. I was suddenly very aware of the gown I was wearing or rather of the fact I was wearing nothing underneath. "Make yourself comfortable, Lisa. I will be doing a regular exam of your body and it's responses." I was far from 'comfortable', but.