Green’s Dictionary of Slang

1. (US black) the tongue.

2002

BodyBoy.com 🌐 I just stuck out my licker as far as I could and pa rammed it right on through it bled like a stuck hog but it was worth it.

2. (N.Z. prison/US gay, also lick, licklick) one who performs oral sex, usu. a lesbian.

[1890		‘Neaniskos’ Priapeia Ep. lxxix 77: But may the gods and goddesses deny nourishing food to thy teeth, O neighbouring cunnilinge* (*Licker of coyntes)].
1970		‘Troy Conway’ Cunning Linguist (1973) 131: [of heterosexual cunnilingus] It is a licker’s special because you not only travel upward, you swab from side to side, taking in all points of interest.
1972		B. Rodgers Queens’ Vernacular 52: fellator [...] licker (pej, usually reserved for a lesbian).
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 107/2: lick n. (also licker or licklick) a lesbian.

3. see arse-licker under arse-lick v.