Green’s Dictionary of Slang

chaffer n.2

[chaff v. (1)]

1. [19C] the throat.

2. [early 19C–1910s] (also chafferer) one who banters or teases, a teaser.

3. [mid-19C] the tongue; the mouth.

In phrases

moisten one’s chaffer (v.) (also cool one’s chaffer, moisten one’s larynx)

[19C] to take a drink, to quench one’s thirst.