pinky, n.² — Green’s Dictionary of Slang

pinky n.²

also pinkie

[the image of SE pink as a ‘feminine’ colour]

a passive or ‘feminine’ lesbian.

1949		Partridge DSUE (3 edn).
1966		Trimble 5000 Adult Sex Words and Phrases.
1972		B. Rodgers Queens’ Vernacular.
1982		Maledicta VI:1+2 (Summer/Winter) 132: Pinky (femme or passive lesbian).