Green’s Dictionary of Slang

bow-sow n.

[Chinese or ‘cod’ Chinese]

(US drugs) narcotics.

1938		D. Maurer ‘Lang. of the Und. Narcotic Addict’ Pt 2 in Lang. Und. (1981) 100/1: bow-sow. Narcotics.
1949		Monteleone Criminal Sl. (rev. edn).
1959		J.E. Schmidt Narcotics Lingo and Lore.