So once upon a time there was this pony named Tree Hugger and she really loved to drop acid. How much did she love to drop acid? Enough to make her own acid. Unlike in America, most drugs are legal in Equestria. Most ponies just don't take them because they are actually well-adjusted individuals who aren't depressed messes like most humans are. Also the world is already psychedelic.
Anyway, Tree Hugger had a lot of fans all over Equestria and one of those fans was named Jolly Llama. Now Jolly Llama resold acid he bought from Treehugger to the llamas. Now I don't think we've ever seen a llama in the show but surely they exist somewhere in greater Equestria.
But that's enough about Jolly Llama. Gotta leave some material for the inevitable spinoff, right?