I'm surprised no one has added this to the thread. It appeared in the book (pre-movie, pre-TV show) version of M*A*S*H; the "Blake" in the lyrics refers to company commander Col. Henry Blake.

Oh if I had the wings of an angel
I'd fly to the high Pyrennees
And I'd open an open-air laundry
Specializing in Blake's B.V.D.'s.

Actually considering the tone of the book I'm a bit surprised the lyrics weren't scatologically closer to the ones published heretofore.