The really scatty stuff is (or at least used to be) in a private area in the Naples museum. Michael Grant (and probably others) did a book about those exhibits.
That's probably where it was, then. We had an Italian host, slightly older, who was an archaeologist and who took us there, so he probably got us into that collection. He was so dry and matter-of-fact, it was not really all that titillating; just naughty. It's sort of a part of classical Italian culture to walk up to the line between naughty and nasty and not go over into violence porn as is now ubiquitous around the world. At least, not far over the line—sort of a sexual self-confidence that was in contrast to the Puritan heritage still in the American air back in the mid-60s. If an Italian youth wolf-whistled or made passes at us and we weren't interested, they just smiled and shrugged instead of resorting to put-downs or aggressiveness like American frat boys—if not us, soon there would be another woman who would like them! It was quite an education to note the difference.