A little jokey term from long ago... when we were expected to be sweet and charming and subservient at all times, but were starting to object to the rampant inequality and limitations imposed on us just for being female, we often discussed these issues in groups that we already belonged to, such as book clubs, sewing circles or just groups of friends. Since it seemed such a radical departure from expected behaviour, the phrase was ironic and entertaining. It may have been used in a novel or article and then taken up more widely. I've seen it done in a very sweet and genteel needlepoint.
lol Colby: golly you are a clever one, imagine seeing right through "them" like that! You should be a detective when you grow up!