What does "gan" mean in "White thy fambles, red thy gan And thy quarrons dainty is."

It's a quotation from "The Maunder’s Praise Of His Strowling Mort" in From The Triumph of Wit, by J. Shirley (1707). It is written in 'Cant', which is a kind of criminal underworld dialect.

White thy fambles, red thy gan, [hand; mouth]
And thy quarrons dainty is; [body]
Couch a hogshead with me then, [sleep]
And in the darkmans clip and kiss. [night]

The Maunder’s Praise Of His Strowling Mort

OED

gan,

Etymology: Perhaps connected with gane v.; or possibly < Welsh geneu, Cornish ganau, mouth.

slang.

n.1 The mouth.

1567 T. Harman Caueat for Commen Cursetors (new ed.) Peddelars Frenche sig. Giiv Gan, a mouth.

1652 R. Brome Joviall Crew ii. sig. F4v This Bowse is better then Rom-bowse, It sets the Gan a gigling.

1785 in F. Grose Classical Dict. Vulgar Tongue (at cited word)

Mouth, lips but also the throat. The term is probably of Welsh origin and referred to fish. GDoS has a very early usage example:

gan n. (also ganns, gans)

[? Welsh geneu, Cornish ganau, mouth; Scot. gane or ganne, mouth, orig. of a fish; itself linked to Norw. gan, a fish-gill]

(UK Und.) the mouth; in pl., the lips; occas. the throat.

• c.1535 [UK] R. Copland Hye way to the Spyttel House Eiii: Cyarum by salmon and thou shalt pek my iere / In thy gan for my watch it is nace gere.