What follows is a parody song called The Newly-Dubb'd Jew in a book called Hilaria. The song is meant to be sung to the tune of "Derry Down." I did not do my homework yet, so I can't explain all the allusions (how "Crop" the convert refers to George Gordon, as it seems to, who was "Cods"?, what was "Akerman's synagogue," and who was "Tommy Erskine.")
As you can see, in this lovely song, the convert is about to be circumcised when suddenly his penis speaks, in an appropriately obscene manner. It is scared.