My husband and I pack up the car and start to make the drive to take out step-son to his new college. He has so much stuff, I end up having to sit on his lap with a suitcase between us and my husband.I started to feel something hard. I reposition my ass, but it didn't go away. I also noticed my step-son got real quiet. "It wasn't there when I first sat down." I thought to myself. Then I realized what I was feeling. My step-son was getting a hard on. I really didn't think about giving him a hard on by sitting on his lap. I could feel it still growing. "My god," I thought to myself. "How big is it going to get." I wondered what he was thinking. Does he think I can't feel it between the crack of my ass? I looked down at my legs. My dress had rose up a little more. I could almost see my panties. My step-son's hands was on the seat on each side of me. I wondered if he could see how high my dress had ridden up. I realized I like the idea of my dress being up so high. It gave me a little thrill knowing I could give my step-son a hard on. We only been on the road for about an hour. There was still four hours to go. I knew my husband couldn't see how high my dress was or he would be looking at my legs. The suitcase blocks everything from his view. I felt my step-son shift his body around. When he did his dick ended up on the back of my ass. I kinda wished he would try something. I'm going to have to take the lead here....