Green’s Dictionary of Slang

1. (Aus.) a brothel.

1889

Dead Bird (Sydney) 9 Nov. 1/4: One of our innocent fledglings strolled into Johnnie Solomon’s show-house [...] and had no sooner entered than a charming young creature glided up, gently pressed his hand, and asked him ‘did he feel it?’ ‘Do you like it?’ ‘Would you like to have it again?’.

2. (gay) a brothel, a place where homosexuals can meet openly (sex is usu. performed off the premises).

1941		G. Legman ‘Lang. of Homosexuality’ Appendix VII in Henry Sex Variants.
1965		Guild Dict. Homosexual Terms 41: show house (n.): Usually a place of assignation (rather than a place of prostitution) for male homosexual clients. Some ‘model’ agencies have such a feature.
1986–7		Maledicta IX 146: Many of his [i.e. G. Legman’s] other terms (boy or come-on boy, peg house and show house, dick-peddler, floater, handgig, live one, muscle in, trade) prove he used to know the words and music of gay prostitute slang but is now out of date.