Green’s Dictionary of Slang

flicker n.1

[ety. unknown; ? one ‘flicks’ the contents down one’s throat]

1. (UK Und., also flickery) a glassful of alcohol; thus rum flicker, a large glass; queer flicker, an ordinary glass.

[UK]Head Canting Academy (2nd edn).
[UK]B.E. Dict. Canting Crew n.p.: Flicker, c. a Drinking Glass [...] Rum Flicker, c. A large Glass or Rummer, Queer Flicker, c. a green or ordinary Glass.
[UK]New Canting Dict. [as cit. c.1698].
[UK]Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
[UK]Grose Classical Dict. of the Vulgar Tongue.
[UK]Lex. Balatronicum.
Rambler’s Mag. 1 Mar. 132: Give me a tumbler of flickery and put a steel bar in it (that is a pint of sherry and a quartern of gin, to make it palatable).
[US]Commercial Advertiser (N.Y.) 1 Feb. 2/3: After roystering at the Theatre, they broomed to a neighboring bousing ken [...] one told the landlord to flick him some panea and cassan, [...] while the others commenced smashing the flickers and glims.
[UK]G. Kent Modern Flash Dict. n.p.: Flicker, a drinking glass.
[UK]Flash Dict. in Sinks of London Laid Open.

2. (US) a state of tipsiness.

[US]Judge (NY) 91 July-Dec. 31: Flicker - a little wee 'bun'.