Green’s Dictionary of Slang

used to describe a way of having sexual intercourse in which entry is made from the rear; thus dog position n., sexual intercourse in this position.

1680		School of Venus (2004) 34: He once more thust his Prick into my Cunt, and Fucked me Dog fashion, backward.
1880		‘Lady Pokingham’ in Pearl 10 Apr. 30: You’re a cheating little bitch, and I mean to have you dog fashion.
1888–94		‘Walter’ My Secret Life (1966) I 79: Something incited me to do it to her dog fashion.
1927		‘J.M. Hall’ Anecdota Americana I 133: He [...] began operations at once in his favorite position, the one variously known as dog-fashion, the cow-couple, all-fours, et cetera.
1944		joke cited in G Legman Rationale of the Dirty Joke (1972) I 63: Six year-old child: ‘Look at those dogs playing around.’ Eight year-old child: ‘They’re fucking.’ Ten year-old child: ‘Dog-fashion too.’.
1949		H. Miller Sexus (1969) 142: We went at it again, trying it dog-fashion this time.
1966		Trimble 5000 Adult Sex Words and Phrases.
1974		(con. 1940s) E. Thompson Tattoo (1977) 225: Then old Buck comes around and plugs her dog fashion while she’s goin down on me.
1979		Maledicta III:2 231: To fuck the ass off someone doesn’t necessarily imply either anal intercourse or homosexuality [...] any more than the hetero person’s getting a piece of ass means doggy fashion.
1980		Maledicta IV:2 (Winter) 198: If she brings her legs up to raise her bimbo so she is in the knee-chest or knee-elbow position, they are said to be doing it dog-fashion or dog-style.
1985		O. Hawkins Chili 37: It was smaller than we thought it was. I had terrible thoughts of being caught, doggie-fashion.
1988		N. Eastwood Gardener Got Her n.p.: Mike flipped her over into the doggy position and she quickly got her wish. He sank his hot prick into her greedy pussy hole.
1993		K. Lette Foetal Attraction (1994) 185: A charming piece of graffiti caught her eye: ‘Never mind the love and passion; whack it up her doggy-fashion’.
2000		Indep. Rev. 19 Jan. 7: 99 per cent of the straight couples said the doggy position was best.
2001		OnLine Dict. of Playground Sl. 🌐 dog, doggy v. to have sex; usually vaginal (occ. anal) but effected whilst the female is in a kneeling position. Also seen in the form ‘Doing it doggy fashion’.