Q, are you saying that Hugill gave a definite meaning for the phrase "do do" as it was used in the chantey as given by Barry Finn in his 10 Mar 09 - 12:49 AM post:

"As I roved out one morning
away you roller bowler
I met a duo dou fair"

"Darling do do I'm going to St Peter's"
Darling do do I'm taking you with me"

-snip-

Or are you saying that Hugil said he was told that the phrases "do do, loulou, doodle" filled out the line", and were used "indescriminately" and never had any other meanings in any songs?

If Hugill said that "do do" never had any meaning but nonsense words to fill in the line because his Bajan informants told him this, I wonder if any of his informants were from the French speaking Eastern Caribbean islands, or if they were aware of the use of the term "dou dou" in those islangs (and elsewhere?).
Maybe his informanats did know this, but they were jivin him, to use a word from this current thread)

If Hugill gave the specific meaning for this phrase in this particular song, I'd appreciate it if you would post that quotation.

It seems to me that it's possible that "do do", "doodle" and other similar phrases could have been used to mean nothing in some songs, and could have been used to mean something specific in other songs.

I think that we may never really know what "do do" means in this particular song or in some other songs from those times.

Regardless of what the meaning of "do do" really is in this song, I'm glad to have learned about the meaning of the phrase "dou dou" as it is (and was?) used in some contemporary folk based stories from the Caribbean and as it is still used in nick-naming practices by French speaking Black (and by non-Black?} people.