A preamble, often used, which precedes something that the speaker cannot resist the urge to say (for a variety of reasons including loose mouth).
It is also either or both of the following:
Extremely critical of the person being spoken to, Revealing the true nature of the person speaking.
It is also either or both of the following:
Extremely critical of the person being spoken to, Revealing the true nature of the person speaking.
by verbusaccidentibus February 7, 2010