Green’s Dictionary of Slang

tweak n.2

[tweak v.2 (2)]

1. methamphetamine.

N. Keitner et al. Psychiatric Nursing 524: Tweak is crystal methamphetamine. As one young user of tweak put it: ‘One line can get you going. You get this amped feeling. You have a lot of energy.’.
[US]N. Sheff [bk title] Tweak: Growing Up on Methamphetamine.
www.urban75.com 🌐 crystal meth (crystal methamphetamine, tina, crystal meths, krank, tweak, ice) .

2. a single puff of crack/inhalation of cocaine.

[US]S.F. Chronicle 19 Sept. A1: (Factiva) ‘When crack and the hubbas (cocaine) came out, that’s when things started going down the drain. People were people, but that drug came out and, my goodness, it’s controlling peoples’ lives,’ she said. ‘They’re on a mission when they get the first tweak.’.

3. (US drugs, also tweaks, tweek) crack cocaine; also attrib.

[US]S.F. Chronicle 2 July 6: (Factiva) Cocaine sold as free-base is called ‘hubba’ or ‘ready rock,’ they said. When it is mixed with marijuana and smoked, it becomes ‘fry daddy’ or ‘chewy.’ When you go out to buy cocaine, you’re on ‘a tweek mission.’.
[US]ONDCP Street Terms 22: Tweaks — Crack Cocaine.

In compounds

tweak freak (n.) (also tweak head)

a regular user of methamphetamine, also attrib.

[US]S.F. Chronicle 26 Apr. 32: (Factiva) But a search of the sour-smelling room reveals a few articles of female attire belonging to the blond amid an indescribable clutter of trash on the floor, which includes the glassine envelopes used for methamphetamine. The officers confiscate a syringe. ‘He’s a tweak freak,’ the blond says spitefully. ‘Tweak freak, tweak freak!’.
S. Wolven Controlled Burn 64: He was a tweak freak too, and then he’d apply the heroin brakes for a week.
J.M. Bebé ‘Jitters’ in Concrete Blood 74: 🌐 Now, Kevin was nothing more than a tweak freak. One step away from melting his brain completely out of his skull.
[US]F. Bill Back to the Dirt 157: ’[W]anted to make sure any of the tweak-head dealers [...] didn’t get out of line’.