kerrsutherland:
While I couldn't remember his name, read him when in HS, every book I did read of his had at least a CP reference if not an actual scene or dream. That to me indicated he had an interest. In some ways, it was also reassuring as it meant I wasn't alone in the days before net access was common.
Yes, I'm in agreement with you on that, there's no question in my mind that Robert Heinlein did have pretty strong spankophile tendencies.
Offhand, I can recall an actual spanking (M/F) in
I Will Fear No Evil and another one (F/M) in
Waldo and Magic, Inc (the
Magic, Inc novella), but there are probably at least a couple more which I missed or have forgotten.
There is also a brief reference to the title character giving her children spankings at the end of
Friday, and as you stated there are numerous spanking-related expressions in many of Heinlein's novels...

--C.K.