Green’s Dictionary of Slang

abdicate v.

[pun on SE abdicate the throne and throne n./queen n. (2)]

(gay) to leave a public lavatory in which one is soliciting to avoid interrogation by its attendant or a police officer.

[US]G. Legman ‘Lang. of Homosexuality’ Appendix VII in Henry Sex Variants.
[US]Guild Dict. Homosexual Terms 1: abdicate (v.): Forced to leave a public toilet by an attendant; said of male homosexuals who frequent public rest rooms. Thus, queens are forced to abdicate.
[US]B. Rodgers Queens’ Vernacular.
[US]Maledicta IX 161: When one considers the inventiveness of some gay slang [...] abdicate for a queen forced off the throne she was lurking on in a public toilet.
[US]R.O. Scott Gay Sl. Dict. [Internet] abdicate: to leave a public toilet because a vice squad officer or a toilet attendant comes in. ‘Eric, its time to abdicate the throne to the cops.’.