three-way, adj. — Green’s Dictionary of Slang

three-way adj.

(US) of a prostitute, willing to offer her vagina, anus and mouth to clients; usu. as three-way girl

1943		W. Guthrie Bound for Glory (1969) 343: Cobbers, spiders, three-way riders.
1969		‘Iceberg Slim’ Pimp 97: [She’s] black, eighteen, cute, stacked, and ‘three-way.’.

In compounds

three-way girl (n.) (also ...bitch, ...broad, ...doll, ...wench, ...woman)

a prostitute (or woman) who will offer her vagina, anus and mouth to clients.

1929		‘Investigator Reports, 1927-1929’ Committee of Fourteen Papers 7 Feb. 45–6: He asked her, ‘Do you French?’ (street slang for oral sex) and she said, ‘Yes, more than that.’ [The investigator] asked her what she meant and she claimed to be a ‘three way girl.’ He asked her to be specific and she explained, ‘the natural way, and up the rectum and french.’.
1931		J.T. Farrell ‘Big Jeff’ in Short Stories (1937) 51: Listen brother do you want me to fix you up with a real broad . . . a three-way doll.
1934		‘J.M. Hall’ Anecdota Americana II 23: Jack, you’ve always told me how much you like three way broads.
c.1940		‘Sonja Henie and Tyrone Power in “Hot Stuff on the Ice”’ [comic strip] in B. Adelman Tijuana Bibles (1997) 119: ‘Three way girl – ain’t you Henie?’ ‘If I had another hole I’d be four ways.’.
1949		A.B. Hollingshead Elmtown’s Youth (1975) 298: The new ‘three-way’ girl Pete just brought down from Chicago.
a.1963		‘The Fall’ in D. Wepman et al. Life (1976) 81: She was a three-way wench, played Jasper in a pinch, / And took ’em round the horn.
1974		(con. 1945) M. Angelou Gather Together In My Name 160: Clara runs a straight house. No three-way girls and no freak parties.
1979		‘Iceberg Slim’ Airtight Willie and Me 57: Stole the finest three way silk bitch in the Apple.
1984		W.J. Caunitz One Police Plaza 34: I’ve a date with a three-way broad with her own mattress.
1997–2002		Alt. Eng. Dict. 🌐 threeway woman (adjective noun) woman who lets the male gender be introduced orally, in her vagina and in anal intercourse.