Syrup, or "Sizzurp" is normally Kool Aid, 40 oz. (Malt Liquor), and couph syrup mixed together. It's high in alcohol and Codine, addictive and deadly, the kool aid is just there to water it down and make it sweeter.
PS - Andy and I hope Lil' Wayne dies a 1,000 deaths, 998 of them from Sizzurp, one from Andy raping and sodomizing him, and one from me pulling his intestines through his eye sockets.