I was sucking guys off in cars too at his age. There were not a lot of other places available to do it. There were parking lots in town known for gay cruising that I would visit and lots of horny men of all ages ready to satisfy my lust for cum.
Car sex is a very good sexual trip. Sometimes, it gets a bit cramped, but worth it. I personally prefer restroom play, starting at a urinal. Peeking down at each other's cocks, commencing stroking, and - perhaps - moving to a stall with a stool makes for more room, which makes for more pleasure. I've had countless scenarios of the latter, with guys from 18 - 80. Great pleasure. I also REALLY love cyber play - on Skype. Two or more guys on cam and mic, stroking and moaning and discussing past pleasures and hoped-for actions. If you are also open to cyber play (cam and cum on audio and video), my Skype ID is New Resident. As long as you are of legal age of consent or older, you're welcome.