Green’s Dictionary of Slang

goose (and duck) n.

sexual intercourse.

1889		Dead Bird (Sydney) 28 Dec. 7/1: Says Mrs A., ‘What are you going to have for your Christmas dinner?’ says Mrs B., ‘Well, if Joe is at home I will have a good goose, but if he is not at home I do not know what I will have’.
1890–1904		Farmer & Henley Sl. and Its Analogues.
[1913		Sport (Adelaide) 3 May 12/1: They Say [...] That Percy W is very loving with his intended wife. Six nights a week he asks her does she like poultry].
1944		Maurer & Baker ‘“Aus.” Rhyming Argot’ in AS XIX:3.
1960		J. Franklyn Dict. of Rhy. Sl.
1969		S.T. Kendall Up the Frog.
1992		R. Puxley Cockney Rabbit.
2001		K. Sampson Outlaws (ms.) 74: The tarts in there, all partied-up, ready for their once-a-year goose on the sly.
2003		B. Dark Dirty Cockney Rhy. Sl.