I am somehow not at all surprised that there are a lot of parodies of this song. That said, the one I've heard most often in my particular orbit is none of these, but rather the talking-blues version by master filk/folk artist Frank Hayes:

Like A Lamb to the Slaughter (studio version) (live version)

One high, one holy holiday, on the first day of the year,
Little Matty Groves to church did go, some holy words to hear.
When in came old Lord Arnold's wife, and she looked at him and said,
"Come here often? What's your sign?" And off they went to bed.

In the interests of brevity, I'll omit some of the more disposable parts of the song, like the section where they get undressed...

...all forty-seven verses of it.

Now old Lord Arnold he had a page; when he saw what they had done,
He said, "I'd better tell the boss!" and he began to run!
He ran through the briars and he ran through the brambles,
Ran through the bushes where a rabbit couldn't go,
Ran so fast that the hounds couldn't catch him,
Down the Mississippi to the--

You get the idea.

Next morning the happy lovers awoke, took one look at who was standing at the foot of the bed, and said, "Ohhhhhhhhh, shit!"

"Rrrise oop, rrrise oop noo, Matty Grrroves, put yuir clo'es on quick's ye can,
Ne'er let it be said that in a' Scotland I slew a naked man!
And ye shall have the be'er sworrrd, and I shall have the worrrst,
And I shall strrrike the second blow, for ye shall strike the firrrst!"

Stupid Scottish twit.

Again, in the interests of brevity, I will omit the part where Matty, for perfectly obvious reasons, takes his own sweet time about getting dressed again...

...all forty-seven verses of it.

Now the first blow little Matty struck, it hurt Lord Arnold sore;
The second blow Lord Arnold struck, little Matty stood no more.
Lord Arnold felt about himself, to see where he'd been cut:
He looked, and found to his surprise he'd lost his -- you-know-what.

And he said "Ooohhhh, shit!"

Now if he hadn't let Matty Groves strike first he'd never have lost his dong,
And if she hadn't let the pageboy know you'd never have heard this song.
And now they sit at home a lot, becoming nervous wrecks,
Which goes to show discretion is the better part of sex.

Moral of this story? Be good.
If you can't be good, be careful.
And if you can't be careful -- try and keep it down to five or six verses, huh?