Green’s Dictionary of Slang

sexual intercourse.

1979		K. Bonfiglioli After You with the Pistol (1991) 316: The only sovereign cure [...] is a brisk five minutes of what Jock coarsely calls ‘rumpy-pumpy.’.
1989		Viz June/July n.p.: Are they having rumpy pumpy at the Palace?
1993		K. Lette Foetal Attraction (1994) 57: Fancy a bit of rumpity humpity with that little number.
1998		M. Newall ‘Sir Gawayne and the Grene Knight’ in Indep. Weekend Rev. 26 Dec. 1: He settles for a snogge. Wythe no rumtie-tumtie.
1998		I. Welsh Filth 35: Could do wi getting doon there again for a bit of rumpy-pumpy.
1999		Indep. Rev. 10 Sept. 8: I indulged in a spot of rumpy-pumpy with a hearty filly wed to a former naval officer.
2000		J.J. Connolly Layer Cake 193: I wish I had a horny young man here with me now, who’d really appreciate a nice bitta rumpy-pumpy.
2001		‘Randy Everhard’ Tattoo of a Naked Lady 137: Butterfly and her backdoor man were making with the humpy-pumpy.
2002		in ‘Ben Trovato’ On the Run (2007) 18: I was expecting a flood of letters from sympathetic females offering me a little rumpy pumpy on the side.
2003		McGill Reed Dict. of N.Z. Sl. 176: rumptypumpty A bout of enthusiastic sex.
2015		I. Welsh Decent Ride 76: A burd’s minge is meant tae be hot for the rumpy-pumpy.
2017		T. Spicer Good Girl Stripped Bare 330: sexual agency? I hear you ask. Is that spy agency with lots of rumpy pumpy?
2018		T. Pluck ‘Cronus Club’ in Life During Wartime 35: [Y]our great-great-grandfather bribed some rumpy-pumpy out of a Puritan milkmaid [...] on the Mayflower.