"Sippin on some syzurp" or "Sippin lean"...Ever heard of it?..! lol

I know some of you have heard the song "Sippin' on Some Syzurp" by Three Six Mafia. But do you know what the song is really about? I never did, but I recently found out, and was kinda shocked at what they mean by "Syzurp". "Syzurp" is common in the south I guess, in places like Houston and the ATL. Its actually mentioned in a few rap songs now that I think about it. They take soda (I think preferably Sprite, not sure), and mix it with Codiene (and Promethazine, whatever that is) cough syrup, and becoming high off this concoction is known as "leaning". LoL, I was like "what the fuck" when I heard this. Cuz they talk about it like its Cristal or something, but it seems like a strange way to get fucked up. So, just wondering if anyone has ever done this?? LOL, I'm guessing the feeling of "leaning" would be an opiate like nod or something...anyway ...leave some feedback....

PS..I saw something on this subject on erowid.com in the "Ask Erowid" section.

It's promethazine syrup, a lot of thugs in my area drink that shit - very strong.