I absolutely LOVE to jack off in cars, especially sportscars and big trucks. In fact, I have a story to go with that.
When the '04 F-150 came out I absolutely fell in love with it. I HAD to drive one to release some tension. I went down to the local dealer wearing a T-shirt and board shorts. I had a plan...
The dealer I went to is known for letting you take vehicles for joyrides. Nobody with you and you can be gone as long as you want. I picked out this big, lifted, F-150 with deep window tint off the lot. As soon as I left the lot I got super-horny. I pulled behind a grocery store, pulled my shorts down and rolled on a condom to stay clean. Then, I got back on the road with my bare butt cheeks in the truck's soft seat and the tunes turned waaay up. I filled two condoms in the course of about 5 hours of driving and wanking.
When I returned I felt really cool, it was so risky. The salesman had NO idea what I had done in that truck and he'll never know, because I didn't leave a trace. In fact, the risk turns me on so much I've done it a couple more times in a Mustang GT and a Cadillac DTS.
The Caddy was tough. The seat is so soft and deep it's hard to wank and drive at the same time. You keep sinking down. Suprised I didn't get pulled over for "drunk driving" for that one.