Dave the Gnome wrote, Only to a dirty mind! :-)

Um -- if you don't have a dirty mind, what are you doing singing "Watkin's Ale"? :-)

Seriously -- everyone knew it was dirty. Chappell's Popular Music of the Olden Time, e.g., printed the tune but said that the text was not suitable for publication, and the early printings, uncharacteristically, omit the printer's name.