Here’s a fun photograph, more fashion portrait than spanking porn, but it nonetheless features Serge Gainsbourg posing as if to spank the lovely and somewhat notorious actress Jane Birkin, in the December 1974 issue of Lui magazine:
"...the girls are prepared in the reformatory’s punishment room, naked, lying on their backs on special benches, bound with their legs spread above their heads, shamefully showing the two holes usually hidden..."