If I remember rightly this was one Burl picked up in Glasgow after the 2nd.WW. He stravaiged the streets of Glasgow with a well known Glasgow writer whose name escapes me at the moment, mention of their escapades was published by the writer in a book???? Another song he picked up at the time was the 1946 rewrite of the old country ballad "Carnwath Mull".
The rather risque 4th. verse of the old ballad goes::---

"Aa slippet ma haun doon the neck o her goon
Jist tae gie her bit paps a kittle
Man she writhed and riggled and pretended tae swoon
Jist like a troot that ye"d newly guddle."

I leave you all to garner your own translation of the Scots words in this verse.

Where else in song is there mention of the old country pastime of guddling for trout.?