chapotraphouse

1950s slang

From a dictionary.

butt 3

3 mainly The buttocks or anus:

There are no dates. I googled but I only found this very annoying article where the writer speaks in circles

The Grammarphobia Blog: Is 'butt' short for 'buttock'?

The OED’s earliest US example for “butt” used to mean the hindquarters is from John Russell Bartlett’s Dictionary of Americanisms (1859), which defines it this way: “The buttocks. The word is used in the West in such phrases as, ‘I fell on my butt,’ ‘He kick’d my butt.’ ”

Maybe butthole was a slang term in the late 1800s but it was only a spoken form for many decades after that until some intrepid pioneer had the audacity to put it in print.