First, "blow me down" doesn't refer to wind blowing sailors off decks, but knocking them down with a fist or a belay-pin as a means of discipline and incentive, I believe. It has nothing to do with oral exercises on strange locations. Following from a page about the old shanty: "Blow the Man Down was originally a halyard shanty. Law on the high seas was basically rule with a Fist, and "Blow" refers to knocking a man down with a fist, belaying pin or capstan bar. Chief Mates in Western Ocean ships were known as "blowers", second mates as "strikers" and third mates as "greasers". "

Though Spaw is most renowned for flatus
We know, at heart, he doesn't hate us.
And the deed for which he'll greatly rate us
Is letting Spaw's flatus ablate us!