Green’s Dictionary of Slang

bing n.1

[bing v.2 ]

(drugs) enough of a drug for one injection.

[US] ‘Words Used in Drug Traffic’ in DN V 182: Packages of any of the above drugs [opium, cocaine, morphine] are termed bings.
[US]B. Dai Opium Addiction in Chicago 196: Bing, Bingo, Bang. A shot of drugs.
[US]Monteleone Criminal Sl. (rev. edn).
[US]Anslinger & Tompkins Traffic In Narcotics 303: bing. A dose of a drug.
[US]J.E. Schmidt Narcotics Lingo and Lore.
[US]Wentworth & Flexner DAS.
[US]Eble Campus Sl. Nov. 1: bing hit – variation of bong hit, to take dope.
[US]ONDCP Street Terms 3: Bing — Enough drug for one injection.

In compounds

bing room (n.)

(US drugs) a room where narcotics users gather to take drugs, a shooting gallery n.

[US]V.W. Saul ‘Vocab. of Bums’ in AS IV:5 338: Bing room—A room wherein drug addicts meet to ‘cook up’ their drugs.
[US]Irwin Amer. Tramp and Und. Sl. 28: bing room.—A resort or room where drug addicts meet to ‘cook up’ or prepare and consume their dose of the drug.
[US]Monteleone Criminal Sl. (rev. edn) 23: bing room An opium den.
[US]J.E. Schmidt Narcotics Lingo and Lore.