Isn't this it, right here at our lovely GT?
https://www.gaytorrent.ru/details.php?id=697e841de00f46370f35bb545598e671b14ab16cffb4880b
If you like "non-porn erotica," "voyeur nudism," etc., this film is a MUST!
Done like a proper documentary (just with lots of handsome guys of all ages and types, and more penis close-ups than I could believe,,,).