You might want to check out Dover Publications. They published a thing called "The Erotic Muse" 40 or so years ago. I've never been able to put my hands on it, but have seen some references to it. One Dover book I do have is "Barroom Ballads" by Frank Shay & John Held, Jr., first Published in 1961 as a re-publication of two works fro the late 1920's. ISBN 0-486-20946-6, Then there's "Bawdy British Folk Songs" by Tony McCarthy, 1972, Wolfe Publishing Ltd., London. ISBN 7234-0492-5. It's a start, anyway.