debut, n. — Green’s Dictionary of Slang

debut n.

[play on SE debut, pun on come out v. (1e)/SE come out, i.e. of a debutante]

a first homosexual experience, a ‘coming out’.

1934		L. Levinson Butterfly Man 42: ‘[I] know how you feel tonight. It’s your début, isn’t it?’ [Simes:DLSS].
1941		G. Legman ‘Lang. Homosexuality’ in Henry Sex Variants 1 427: Soon after Daniel made his début he met another queen in a café and they became loyal friends.
1965		K. Marlowe Male Homosexual 89: The big event of the year is the debutante ball. That’s when new members who have never been ‘brought out’ can make their debut [Simes:DLSS].
1966		Trimble 5000 Adult Sex Words and Phrases.
1974		‘A. Peters’ Happy Hustler 36: They all fucked him up the ass. ‘Gee, five up the ass for a debut!’ [Simes:DLSS].
1985		S. Payne Beat 24: There was another wig he had worn once years ago when Golden Boy had made his debut at the club [Simes:DLSS].