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!