i've never listened to fictional erotica in the car, but i was super horned up one day on the computer surfing porn, and i was really into amateur/hidden camera stuff during that particular session.
I stumbled upon an audio recording some dude made of him and some older woman, don't remember who she was, but it was obvious listening to the audio that they weren't supposed to be doing anything. My first reaction was obviously "this is bullshit set-up pro-am porn," but after listening for awhile, it was clear that it must have been legit. There was at least 20 minutes of them eating, with hardly any words spoken, just eating in silence. the set-up was so obviously something that seemed like it wasn't staged, that it was a huge turnon.
anyway, i had to leave but was still rock hard and edged up but i had to leave, so i found the link on my phone and played it over bluetooth in the car. i've NEVER done this before, but i beat off while i drove, listening to this hidden audio of these two fucking! luckily i had an empty cup in the car that i nutted into for easy clean-up, but it was awesome.
if i stumble upon the file again i'll share!