1. To make a fool of yourself by getting caught doing a deceptive or untruthful act (such as lip syncing) and blame it on external circumstances such as acid reflux disease, a drummers timing pressing a button, track performance order etc. To pull a genuine Ashlee Simpson one must "do a hoedown" (or some similar bizarre and out of place act) once caught.
n. The point that must be exceeded by exposure to crappy music to begin producing the given effect or result, or to elicit the response of, preferring to listen to the music of Ashlee Simpson.