Now the thing that you need to know about Equestria is that just because most drugs are legal doesn't mean anyone can make them. You have to get licensed to do that shit, and Tree Hugger's LSD was definitely not licensed. So one day Celestia had her arrested after a no-knock raid on her house. But Celestia is a cool cat so she told Tree Hugger "Look I know you've been holding out on me. You've got the best stuff in Equestria and you didn't even bother to get licensed so you could sell it properly? And you know who's the official tester of acid? Me. So pony up a 10 strip and let's get wriggity wriggity wrecked, bitch!"
So Celestia and Tree Hugger did acid together, and Celestia had such a good time that she made Tree Hugger a licensed vendor on the spot so she didn't have to go through a bunch of bureaucracy. But that's another story for another time, eh?