Chocolate was always used to describe MJ when we had to right about that. Powder alone, making it look like a food ingredient was the code used for Coke. Nicknames like Lex, or Mitty were used for opiates and benzos. The list is long same with "creative" vocabulary. But at the end, it would function in the same way as SWIM functions here. "We know that's you."
By the way LSD were called stamps, like postal stamps because we used to get them in real stamps. We have never had any problems with that one, but looking back I see this wouldn't protect myself and we were just feeling a false sense of protection, although nobody was ever caught because of this wording.