Well, definitely do not binge eat before the plug. In fact, eating (and sometimes drinking warm drinks) can stimulate you to poo. That would be fighting the plug.
Defiantly poop first. A full enema isn't required, but a "quick little rinse" of the rectum is a good idea if you want to stuff for a while out in public.
At home is more flexible, you can always pull it out, poop, and clean it whenever you want to.