Green’s Dictionary of Slang

drift v.2

[ply on SE snow drift / snow n.1 (2a)]

(US drugs) to be under the inluence of cocaine.

[US]Seattle Star 11 Nov. 8/3: Key to Broadway Slang! [...] Hesitate, hesitate, boy, you’re drifting. [Just a minute, just a minute, boy, you’e full of cocaine].