Yzma and Kronk

Before drinking a toast to Kuzco's rule, Kronk stealthily informs Yzma that he's poisoned all three drinks (due to losing track of which one was initially poisoned). To this end, while Kuzco isn't looking as he drinks, Yzma dumps her drink in a cactus pot while Kronk uses forced perspective as he pours it over his shoulder.

Example of:
Discreet Drink Disposal