Whiskey in the jar - an ethnomusicological exploration

Background
The band always joins in on the chorus to Whiskey in the jar. The
problem was that they all very obviously sang completely different
words, so at one band practice (honest!) they agreed to sort it out.
Here is an abbreviated version of the emails that followed.

From: Robin
Subject: Dictates mayhem and music
Date: Mon 15 May 2006
Whiskey in the jar - no guarantees but I think the words are:
Mush a ring der a du ra da
Whack fol a dad i o (x 2)
There's whiskey in the jar

From: Kiff
Subject: RE: dictates mayhem and music
Date: Mon 15 May 2006

I'm speechless! I think I will just let Robin sing that bit...

From: Colin
Subject: Mayhem and madness
Date: Mon 15 May 2006
Are there enough syllables? Could there be just one more? It would fit better:
Mush a ring der-a-do der-a-da

Two months later:
From: Colin
Subject: Mushy peas dungarees kangaroo
Date: Wed 5 Jul 2006
Is it wack for the daddio?

From: Robin
Subject: RE: Mushy peas dungarees kangaroo
Date: Wed 5 Jul 2006
Mush a ring dum a dum, I'd say. I love the confusion.

From: Nigel
Subject: Re: Mushy peas dungarees kangaroo
Date: Wed 5 Jul 2006
It is wack fol me daddio, with a skiddery-I and, if I might add, dee di.

From: Kiff
Subject: RE: Mushy peas dungarees kangaroo
Date: Thu 6 Jul 2006
On the subject of Whiskey in the Jar (mush aroo about nothing, methinks)
I couldn't stop myself from searching a few lyrics websites.
I found four covers:
Dubliners:
Mush-a ring dum-a do dum-a da
Wack fall the daddy-o, wack fall the daddy-o There's whiskey in the jar
Thin Lizzy:
Mush a rain dom a do dom a da
Whack for my daddyo whack for my daddyo
There's whiskey in the jar-o
Grateful Dead:
Musha ringum duram da
Whack-fall the daddy-o
Whack-fall the daddy-o
There's whiskey in the jar
Metallica:
Musha rain dum-a-doo dum-a-da
Whack for my daddy-o
Whack for my daddy-o
There's whiskey in the jar-o
No agreement there then...

From: Colin
Subject: Ma's earring, dumb hairdo, damaged arm
Date: Thu 6 Jul 2006
See what google has to say, and all will be revealed.
Or, just possibly, not.
The most widely sung version is, apparently, musha ring dumma do damma da.
I'm sticking with mushy peas etc

From: Nigel
Subject: Mu-sha ring-um du-ram da, whack fol the daddy-o, whack fol the
daddy-o, there's whiskey in the jar
Date: Thu 6 Jul 2006
Esteemed colleagues
I had no idea what a scholarly (though not on the road) band we were.
Kiff and Colin are clearly Dean and Professor Emeritus of Pogue Studies,
Faculty of Dubliners at McGowan College, Cambridge.
Dr Paddon sets out a myriad of possibilities, tracing the lyric through
orginal Celtic verse through to thrash metal and beyond. Professor Gamm
however explores the dual sources of Australian marsupials and workwear
(his dungaree/kangaroo hypothesis) The Dean, however would no doubt
see it is a fluid construct, reinventing itself through the years, and
through his performance as the mood takes.
For my part (GCE woodwork, school of hard knocks and University of Life)
I would just be glad if someone told us what it was so we could all sing it.
What are we, Genesis?
Yours for common sense and the common touch

Footnote:
The band settled on Mush-a-ring dum-a-doo dum-a-dah,
whack-fol-the-daddy-o.
To this day they all still sing different versions