That translated maybe perfectly innocent but to me it sounds like ahh go fach yerself
Doh!
Yes, which is why it so very often used by comedians - to get a cheap laugh from the uneducated. Sadly, it continues to raise a giggle. They must have been telling that one for a hundred years or more. Always works.
Its Scots (as CarterUSM instantly recognised).
The verb, like many other Scots words comes from the French. In this case, from
fâché (= to anger) and used in Scots to mean "to distress"
i.e. = Don't distress yourself about it / Don't be angry with yourself.
Even the reflexive construction is more French than English!
I won't, but you could bile na heid and make daft soup.
Now we're talking! But I'm a vegetarian. (See what I did just there?)
Just don't start the Gaelic on here. Latin I can cope with, but the Gaelic . . .