A rather curious expression the grew out of the arcane community. It has seen widespread entry into colloquial usage and is used to mean to one has overstayed their welcome or has talked so much that everyone else wants them to shut up.
It originally was a reference to Rendorii and how its often quirky word construction. More than one arcane student has burned the night oil trying to master the ins and out of the language in order to master magic. That definition came to mean something onerous or difficult among the arcane students and soon entered its way into the common vernacular to the definition we know today.