Would this ever work as slang for marijuana? As far as I know iarbă (grass) works but tigaie (pot) doesn't. I need to know these things ;)
I can only speak for the regions I know (mostly Bucharest and Oltenia), but I've never heard it used that way. "Iarbă" is the most popular term.
As a note, the slang "pot" for marijuana is not related with the cooking utensil, but probably with the Mexican word for cannabis leaves: https://en.wiktionary.org/wiki/pot#Etymology_2