Herre's McGonagall writing in Scots rather than English, and, surprise surprise, it's not bad, and I'd say quite simgable. It's a temperance song which is not teetotalitarian, which is a sensible enough position:

Here are we met, a very merry set,
And a jovial set of boys are we;
And we'll drink and sing an mak the tavern ring,
Owre a we drap o' the barley bree.
Chorus-- Sae we'll no get fou,
We'll no get fou,
For that wad spoil a' the spree;
Sae we'ill tak a wee drap,
And hae a social crack,
Owre a we drap o' the barley bree.

And as we've a' met thagether to hae a spree,
I houp nane o' us will disagree,
By getting owre fou, until we spu,
By taking owre muckle o' the barley bree.
Chorus-- Sae we'll no get fou,
We'll no get fou,
For that wad spoil a' the spree;
Sae we'ill tak a wee drap,
And hae a social crack,
Owre a we drap o' the barley bree.

I found that in this thesis about McGonagall - The Heroic Warrior, which sets out to put him in his context. An interesting read.