Inertia of the mouth. The inability to stop talking once one has started, often including the verbertia itself in the torrent of words. Could also apply to the inability to *start* talking again once you've stopped (usually while taking a dramatic pause during a speech).
"I just meant to answer the question with 'I'm having a nice day, thanks,' but verbertia set in, and I ended up telling her my whole life story from DNA up until that afternoon."
by Zen Render November 10, 2004