1. Comedian Mitch Hedberg refered to "pancaking" as starting out strong, but then halfway through your act, the audience is sick of you. Kind of like when you eat a lot of pancakes; they're great at first, but by the end you're like "jeez, that's too much".
2. Street for "crack". (See Family Guy)
1. Most "featured" comedians -- not headliners, but the people who come before them -- pancake halfway through their act.