subs. phr. (old).The posteriors: see BUM.
1709. WARD, A Compleat and Humorous Account of All the Remarkable Clubs and Societies in the Cities of London and Westminster (1756), 14. To keep their laxative BUM-FIDDLES from dishonouring their sheets.
Verb. (venery).To copulate: also BUMFIDDLEDUMDICK: see GREENS and RIDE. BUMFIDDLED = (1) deflowered; (2) = pregnant.
1620. FLETCHER, The Chances, I., v. And am I now BUM-FIDDLED with a bastard?