The Foggy Foggy Dew

(Song begins at 3:56)
I figured out what the foggy, foggy dew refers to: it's literal. The situation is just being described ironically, since one doesn't really need to be saved from the foggy dew, so much. A lot like the song "Baby, It's Cold Outside". The really nice thing about this song, desite it's bawdy (if subtle) punchline, is that the guy becomes a single dad! That's cool. You raise that kid, brother.

Traditional
Rise Up Singing chapter: Time and Changes, p.223
D GE A D / D GE A D / A D A D / D GE A D

When I was a bachelor, I lived all alone, I worked at the weaver's trade
And the only, only thing I did that was wrong was to woo a fair young maid
I wooed her in the wintertime and part of the summer, too
And the only, only thing I did that was wrong was to keep her from the foggy, foggy dew

One night she knelt close by my side when I was fast asleep
She threw her arms around my neck, and she began to weep
She wept, she cried, she tore her hair. Ah, me! What could I do?
So all night long I held her in my arms just to keep her from the foggy, foggy dew

Again I am a bachelor, I live with my son, we work at the weaver's trade
And every sing time I look into his eyes he reminds me of that fair young maid
He reminds me of the wintertime and of the summer, too
And the many, many times that I held her in my arms just to keep her from the foggy, foggy dew