Green’s Dictionary of Slang

1. to have sexual intercourse.

1836		‘Come, Draw Your Peg, My Rum One’ in Cockchafer 21: Ah, now, your peg you’re fixing, fixing, fixing, / Drive it in quite boldly! Oh, a’nt this rummy fun?
1857		Venus’ Miscellany (NY) 31 Jan. n.p.: I saw a copy of your merry love paper, in which [...] Kate told how her cousin Bob did it to her; amd I want to tell you how cousin Bob fixed me.
1934		B. Appel Brain Guy (1937) 117: ‘I’m tired knocking off Madge, the little slut.’ [...] ‘Tired fixin’ Madge.’.
1935		(con. 1920s) J.T. Farrell Judgement Day in Studs Lonigan (1936) 534: I’m figuring to fix that baby again.
1957		G. Metalious Peyton Place (1959) 302: I’ll fix ya. Same’s I used to fix you long ago.
c.1960		in E. Cray Erotic Muse (1992) 304: If all the young ladies were little white vixens, / And I were a fox, I would chase them and fix ’em.
1981		J. Bradner Danny Boy 65: One day he’d get between those meaty white legs, and when he did, he’d fix her good!

2. to make pregnant.

1966

M. Rumaker Exit 3 and Other Stories 75: Say a fella gets a girl fixed good and them not being married.