Green’s Dictionary of Slang

1. a small glass of beer.

1893		Illus. Police News 15 July 4/2: I’ll go and relieve my mate Tony, so that he can come down and have his tiddley.
		Illus. Police News 9 Apr. 11/3: His Honour: Was the barmaid drunk? Defendant: Certainly not. [...] Plaintiff: Go on, now; you know she’d had a little drop of tiddley (Laughter) .
1906		Sun. Times (Perth) 4 Nov. 4/8: And squatters [...] / Blow the froth from tanner tiddleys.
1911		Truth (Sydney) 2 July 1/4: Not so bad to pay a tanner for a pint, but it’s too much for a ‘tiddley’.
1924		E.G. Murphy ‘Pints That I’ve Refused’ Dryblower’s Verses 60: But grant, O Satan, as I scorch, / A tiddley now and then.
1937		E. Raymond Marsh 347: Have your tiddley, by all means; it’ll do you good.

2. (Aus.) a threepenny bit [the smallness of the coin].

1941

Baker Popular Dict. Aus. Sl.

3. see tiddleywink n.²

4. see tiddly n.