Changing the subject slightly, I watched "Of Freaks and Men" again this week. It still gets my vote for the greatest spanking movie of all time. Not only are there truly memorable spanking scenes (mostly F/F), but the whole film is a masterpiece: surprising, troubling, visually arresting, thought provoking and utterly unpredictable. It's currently available in full on Youtube:
https://www.youtube.com/watch?v=TkqA_rL66XIUnfortunately it's in Russian and there are no English subtitles, but I've found that even without understanding the dialogue it's possible to get the gist of what's going on - especially after watching it several times!
Possibly less well known is the excellent spanking scene in "The Toilers and Wayfarers". I know M/m isn't to everyone's taste, but it feels to me like an unusually authentic depiction of a domestic punishment:
https://www.youtube.com/watch?v=jybI9HJjZ6AIf you want to cut to the chase, it starts around 29 minutes in!