Jon,
It just occurred to me that people your side of the pond might find a collated English text of 'Knife in the Window' useful. This is collated from the versions of Harry Cox (Norfolk), Bill Whiting (Berkshire) and Jack Barnard (Somerset) as shown.

Last Saturday night young Nancy laid sleeping x2
And into her bedroom young Johnny went a-creeping
With his long fol-the-riddle-ido right down to his knee. (HC)

He said Lovely Nancy, may I come to bed to you x2
She smiled and replied, John, I'm afraid you'll undo me. (HC)

Now the door it is bolted and I cannot undo it
The door it is bolted and I cannot undo it.
O now she replied you must put your knee to it. (BW)

So I put my knee to it and the door flew asunder x2
And upstairs I went like lightning and thunder. (BW)

My breeches fit tight, love, I cannot undo them, x2
She smiled and replied, John, you must take a knife to them. (HC)

My knife will not cut, love, it ain't worth a cinder x2
She smiled and replied, John, there's two on the window (HC)

He picked up the knife and he unrest his breeches x2
The knife it was sharp and it cut through the stitches (HC)

His small clothes fell from him and into bed tumbled x2 (HC)
I'll leave you to guess how the gay couple fumbled (Jack Barnard)

All the night long how they rolled and they tumbled x2
Before daylight in the morning Nancy's nightgown he crumpled (HC)

Now nine months being past it fell on a Sunday x2
A child it was born with a knife-mark in the window. (HC)


The last line of course is a motif found in many comic songs dating back centuries.