I'm not a fan of weed or something just wondering if it's allowed scvonmal saw one
It all depends on which country you are in.
If you are in Germany, where the possession / cultivation / sale of cannabis is illegal, the Twitch TOS forbid you to actively smoke weed in the stream. On the other hand, being high is allowed to my knowledge.
On the other hand, if you are in Portugal, where all drugs are decriminalized, you can also solder one in front of the camera.