Green’s Dictionary of Slang

throne n.

also king’s throne, throne room

[early 19C; 1920s+] a lavatory.

In phrases

pretender to the throne (n.) [1950s–60s] (US gay)

1. a heterosexual who poses as gay for the purposes of avoiding the draft.

2. a vice squad policeman who poses as gay to entrap genuine homosexuals.

sit on the throne (v.)

[1920s+] to use a lavatory.

throne up (v.)

[1920s] to use the lavatory.

SE in slang uses

In phrases