I obtained four more magazines today (at bargain prices, or I couldn't have afforded them), and each one had at least one spanking in it! Honestly, these spankings are more interesting for historical reasons than as erotica - they're obviously-posed F/F for the most part - but one of them is a female spanking a ventriloquist's dummy
It's got to be the weirdest spanking that had appeared in print up to that point, and still startles today. Here's one of the other photos, from the January, 1950 issue of Whisper, which purports to be the plea of a girl who's always getting spanked:
Pretty tame stuff, and we've certainly seen this kind of thing many times before, although it may be marginally better than the more familiar Irving Klaw stuff from just a few years later. Again, what I find most interesting is that spanking could be presented more or less openly in a men's magazine by the late 1940's, the erotic aspects still being thinly disguised to be sure, but there was a market and the publisher was getting away with it despite the objections of would-be censors such are Fredric Wertham. (Wertham hadn't written his "erotic spanking" objection yet since Seduction of the Innocent did not appear until 1954, but it seems clear that spanking was already somewhat under fire even though I've only been able to amass indirect evidence so far.)
Newspaper comic strip spankings do not seem to have engendered any opposition - why that was I still don't know. Perhaps people saw them as purely disciplinary, even though some of them clearly had erotic overtones (Spirit/Ellen, Phantom and Count Jorge/Queen Pera, etc.)