"'The Crabfish' (known also as 'The Sea Crabb'), an English folk song dating back to the mid-1800s about a man who places a crab into a chamber pot..."

"... unbeknownst to his wife, who later uses the pot without looking, and is attacked by the crab. Over the years, sanitized versions of the song were released in which a lobster or crab grabs the wife by the nose instead of by the genitals or that imply the location of the wounds by censoring the rhyming word in the second couplet. For instance, 'Children, children, bring the looking glass / Come and see the crayfish that bit your mother's a-face' (arse)."

From the Wikipedia article "Expurgation," which I'm reading this morning because I'm listening to the new Chris Rock special (on Netflix) and, in an effort to blog it, relying on a sanitized WaPo article and using the word "expurgations/expurgation/expurgate" for the first time in the 19-year history of this blog.

Elsewhere in Wikipedia, there's a whole article on "The Crabfish," complete with full lyrics, which, first, I'm very happy to see after suffering through numerous YouTube renderings of the expurgated song:

In the middle of the night, I thought I'd have a fit
When my old lady got up to a-have a shit
By the way side high diddly aye do.... 

Children, children, bring the looking glass

Come and see the crayfish that bit your mother's arse
By the way side high diddly aye do

Children, children, did you hear the grunt
Come and see the crayfish that bit your mother's cunt
By the way side high diddly aye do.... 

ADDED: The "Expurgation" article has an awfully random collection of examples, e.g.:

The 1925 Harvard Press edition of Montaigne's essays (translated by George Burnham Ives) was published without the essays pertaining to sex. 

A Boston-area ban on Upton Sinclair's novel Oil! – owing to a short motel sex scene – prompted the author to assemble a 150-copy fig-leaf edition with the nine offending pages blacked out as a publicity stunt. 

In 1938, a jazz song "Flat Foot Floogie (with a Floy Floy)" peaked at number two on US charts. The original lyrics were sung with the word "floozie", meaning a sexually promiscuous woman, or a prostitute, but record company Vocalion objected. Hence the word was substituted with the almost similar sounding title word "floogie" in the second recording. The "floy floy" in the title was a slang term for a venereal disease, but that was not widely known at the time. In the lyrics it is sung repeatedly "floy-doy", which was widely thought as a nonsense refrain....

The list ends with the recent idiocy aimed at Roald Dahl’s books (in which "sensitivity readers" endeavored to ensure that the books could "continue to be enjoyed by all today").