You are correct! Couchon de Lait appeared on the Beausoleil CD "Bayou Cadillac,_ which was released in 1986. In the accompanying booklet written by Joe Wilson,
he described the song as follows: "Couchon De Lait (Pig Roast) is Tommy Jarrell's "Sail Away Ladies" given a Louisiana turn and a new title by Dennis McGee (Pigged out" Dennis yelled when he heard the tune, but not in English)."
Speaking of Dennis McGee, there is a great picture of Dennis McGee and Tommy Jarrell together on Evo Bluestein's website. Several years ago, when I saw the picture, I contacted Evo to ask about the picture. He said the he had taken it in 1975 when Dennis and Sady were playing on a tour set up by Mike Seeger. When I contacted Mike Seeger to ask about that tour, he told me to talk with Marc Savoy, who had arranged to heve Dennis on the tour.
I was kind of excited about that picture; so I made a couple of copies of it to give to Bill McGee and Florence Fontenot the next time I went to Louisiana. Well, it turned out that the next time I saw Bill and Florence was at Marc's Saturday jam session. When I gave them copies of the picture, Florence started crying - she had no idea what all her father had done or where he had been. Then she started passing the picture around. Whwn Marc saw the picture, he said, "Yes, I know about that tour."
Later, I happened to be talking with someone who knew Tommy Jarrell well about the picture. She told me that Tommy really liked Dennis and talked about him a lot.
I don't think many people know about that connection, but I think you may have discovered one of the results of their friendship. That's just amazing! Thanks for posting that.