Green’s Dictionary of Slang

(US black/teen) a phr. used to a young woman who has been taken out in a car: fuck or walk back.

1927		‘J.M. Hall’ Anecdota Americana I 120: A fellow invited a girl friend into one of those F.O.W.* cars [*For the benefit of those not au courant with the new additions to the vocabulary of the vernacular we may be pardoned for explaining that F. O. W. is an abbreviation for fuck or walk.].
1962		P. Crump Burn, Killer, Burn! 172: ‘Okay, Cherry, F.O.W.B.’ [...] ‘What,’ she demanded. ‘Screw, that’s what. Or walk back.’.