Back when I was a young scout in England in the fifties, I learned this song at a canp from scouts from Colchester. Again, sung to the CDED melody after each line we sang Oo-OO-OO-oo Ah- ha ha ha with the maniacal laughter rising in intensity after each line. It was a very popular part of our early repertoire with Cobbers, before we got too serious (pity!) and we actually recorded it in 1969 but never released the album. The words we used were:

As you see the hearse go by
Think you may be the next to die

They put you in a wooden box
And cover you up with a heap of rocks

All goes well for about a week
Then your coffin begins to leak

The worms go in the worms come out
They go in thin and they come out stout

Pus oozes out like thick rich cream
And your live turns a ghastly green

Your eyes fall in and your teeth fall out
Your brains come trickling down your snout (loud sniff)

The moral of this story needs no explanation
It's really much better to have a cremation

We used to have a television show in Australia hosted by a fellow called Deadly Earnest. It was all B grade horror stuff etc but was popular late at night and we recorded it because we were going to perform it on his show (we had to mime due to lack of facilities).
Unfortunately, Deadly was killed in a car crash and the whole thing folded. My kids love the song however. So do I.