For anyone who hasn't met her, here's a Sheela-na-Gig. This one is resplendent on the corbel table of Kilpeck Church, Herefordshire, where she has cheered up visitors for centuries.
Her precise meaning isn't certain, academics being too shy to say "Up my wigwam, big boy!" They mention that 'they are often positioned over doors or windows, presumably to protect these openings,' (Bumsquash and Rattlesnake, 1904), when Sheela's probably only there to cheer on any locals trying to have a tuppenny upright. Against the church door.
It's nice to know that the church once favoured causes like this. Modern churches, of course, don't usually have them; but Sheela still finds expression in the Australian colloquialism 'Sheila' which refers to any female woman of the opposite sex - and provides a fascinating insight into the psyche of the Australian male.
The Sheela-na-Gig, in Sligo Town, has also become just another name for another Irish pub, again reflecting the aspirations and expectations of the drinking Irishman. Or, indeed, the Irish drinking man. (Potterton & Wyndebagge, 1932).
Sadly, all this refreshing realism was swept away under the metaphorical carpet during the Victorian era. The Obscene Publications Act 1857 banned works 'written for the single purpose of corrupting the morals of youth and of a nature calculated to shock the common feelings of decency in any well-regulated mind', but an amendment to this Act made by Lord Chief Justice in 1868 included anything that could corrupt, whether this was intended or not. It led to the banning of medical textbooks, bird-spotters' handbooks and the sale of chicken portions.
However, it is questionable whether the Lord Chief Justice really had a 'well-regulated mind'. His name was Cockburn.