Green’s Dictionary of Slang

1. bisexual.

1966		Trimble 5000 Adult Sex Words and Phrases.
2019		P. Baker Fabulosa 299/1: versatile bisexual.

2. (US gay) able to enjoy both active and passive sexual roles.

1964

Lavender Lex. n.p.: versatile: – A homosexual who enjoys both the receptor and insertor roles and who enjoys also both anal and oral relations.