The conversation took a turn towards Monty Python yesterday, and in particular the Life of Brian. This film featured as a character (Brian's putative father) the Roman soldier Nortonus Maximus, a name derived from norton, a slang word for penis.
I was naturally curious as to how a penis could come to be called a norton, but when I went to look it up I was surprised to find the word doesn't appear in Farmer & Henley, nor in Partridge, nor in Green. It isn't even in Urban Dictionary, and I can't find this definition anywhere online. But I can distinctly remember using the word before the Life of Brian was released, and the scriptwriter clearly expected the joke to be understood by the audience.
So, does anyone know the etymology of this word? And does anyone know why it seems to have been overlooked in the standard references?