I'm not sure what area this was shot in, or what country. It certainly seems the road he was on either was so little traveled he could just pull down his pants and mouth hump the other guy right there without getting caught, or was so horny it just didn't matter--his dick was 100% in control.
I've been alone in the car when I've had this extreme urge myself and starting at 3:48 you'll get the idea. Finding the right place, pulling your pants down completely, getting weak at the knees with your mouth wide open having a full-body orgasm. Like this man, it's something I have no control over.