One time when we were on a long drive and I rubbed myself off in my shorts. Mom and dad in the front seat, my sister was reading she had a bikini on with shorts over the bottoms. I was on the sunny side of the car, the son was burning hot, so I put a towel over my legs and slipped my arms under it too.

I started to think about her firm tits and shaved pussy. My cock was hard so I started to rub it through my shorts. I couldn’t help it I was so horny. I know it’s wrong but it felt so good. I know she knew what I was doing because she took her shorts off, pulled her knees up and turned a little so I could see her crotch. She kept reading though. So I rubbed my cock peaking at her from the corner of my eye. Her nipples even started to show. I cum in my pants as quietly as I could, and when I did I seen a smile on her face.

Later when we stopped to go to the restroom she whispered to me “now it’s my turn”. When she came out of the restroom she gave me a big smile. That evening she told me she enjoyed the drive but not as much as you seemed to enjoy it. I said you must have felt much better after the stop me made.