I've been looking for the words of The Marrow Song for quite a while. It was originally from the British music hall stage. I seem to remember that it was originally sung by a man who dressed up as a woman complete with a parasol - "I haven't had it up yet this year !". The words posted earlier are not the original ones, but a modification of them.

In the original the gentleman takes his "marrow" into the sea for a swim and it shrinks (there's a chorus about how small it gets), but then the "lady" singing the song takes him into her room and "I slapped a mustard plaster on and it swelled before my eyes". The last chorus was usually sung -

I've never seen one as big as that,
I've never HAD one as big as that,
I've never seen one as big as that before.

I'll try and find some further details from my old mate John Foreman.