Green’s Dictionary of Slang

(US black) a surreptitious late-night or early morning visit to one’s lover.

1934		Bessie Smith ‘I’m Down in the Dumps’ 🎵 I thought it was that sweet man of mine, makin’ his ‘fore day creep / Wasn’t nothin’ but my landlord, a great big chump.
1941		D. Burley N.Y. Amsterdam Star-News 20 Dec. 14: That truly unhipped Jap ‘fo’ day creep’ in Pearl Harbor.
1994		C. Major Juba to Jive 30: Before day creep n. (1920s–1940s) a secret journey in the night or early morning to see a lover.