Due to some issues with my heart I had to go from my home in Sheridan to Billings to see a specialist. My wife and I left the house about 5:30 AM for my 8:00 appointment. After the visit we went and got something to eat and then went to Costco for some much needed shopping. I always enjoy Costco as there are always some hot women there and today was no exception. There was one there with large breasts and no bra who we seemed to keep coming across. By the time we left my cock had been semi-erect for an hour and leaking precum for about half that time. After we got on the highway, my wife was driving, I laid the seat back to try to sleep but was unable to so I unsnapped and unzipped my jeans and laid the flaps wide for comfort. My wife mentioned that any truck, from pickups to semi trucks could look down and see my cock and balls. I replied that I didn't care, I wanted to be comfortable. It was only about 5 minutes and we were passing a semi. My wife slowed down and matched speed as we got even with the truck part. I glanced up and the driver was looking down so I started masturbating. Soon my wife sped off. I quit jerking and she said "Don't stop now, there's another truck" So I kept on going. This driver was already looking as we drew even, cb communication I guess. Anyway, she kept on doing this and I kept on jerking. Pretty soon my cock, balls and hand were covered with precum. We kept this up for a little over a hundred miles. As we approached the state line I groaned really load and blew my load all over my stomach, hand and cock and balls, while we were even with another truck. The driver blew his air horn as we drove off. My wife and I cleaned up my cum by picking it up with our fingers and licking them off, racing to see who could get the most. I told my wife it was her turn next trip.