I agree. As very horny as I am, cumming while I'm actually driving or rather while the car is moving, is rare. I've done it at red lights while another horny guy in a business truck or van is watching, but that's different. I'll usually pull over to a reasonably private place or parking lot, pull my pants down and just shoot my sperm into a paper towel. I find traffic and driving in general very stressful. The only upside is it increases my sex drive even more resulting in even more powerful orgasms. Just stroking my dick calms me down, and the more aroused I get, the calmer I feel. I just have to make sure I have enough composure to find a place where I won't get in trouble. That's why I can't let myself get too aroused until I find the right place to "go all the way".
Dude, cum in your car all you want but it really is not safe to do it while driving. Its not worth it if you get killed. Nice cock and nice cum shot though.