Green’s Dictionary of Slang

1. (US gambling, also hicks, jimmy hicks, sister hicks) the point of 6 in craps dice; a six in poker.

1898		St Paul Globe (Minn.) 28 Aug. 13/6: Come on, natural. Umph I don’ throwed six. Please, Jimmy Hix. Stay away Mr Debil.
1898		‘The Game of Craps’ in Current Lit. XIII:6 558/2: Nearly every point on the dice is named. [...] six is known as ‘Jimmy Hicks.’.
1919		Wilkins Co. Fund 45: Hicks [a six in craps] [HDAS].
1922		(con. 1918) S.V. Benét Beginning of Wisdom 262: The dice showed three and three. ‘Jimmy Hicks!’ murmured Atropos cautiously. ‘Jimmy Hicks! We are now Jimmy Hicksing, Philip!’.
1932		J.L. Kuethe ‘Johns Hopkins Jargon’ AS VII:5 331: 6 – Jimmy Hicks of the Horse marines.
1944		Amer. N&Q 160/2: Rhyming argot in the lingo of crap shooters (Jimmy Hix, six; Eighter from Decatur, eight, etc).
1951		S. Larsen ‘Vocab. of Poker’ AS XXVI:2 99/2: jimmy hicks. Any six-spot. This name was probably borrowed from the vocabulary of dice.
2001		Word for the Wise 31 Aug. [radio script] A roll of six has a number of names, ranging from sixie from Dixie to Sister Hicks and Jimmy Hicks.

2. (UK Und., also jimmy) an injection of narcotics [= fix n.³ (1)].

1989

J. Morton Lowspeak 81: Jimmy [...] (Can.) an injection of narcotic. Jimmy Hix – a fix of drugs.