The very first coast-to-coast Tea Party was April 15, 2009. That was the night Anderson Cooper and Wolf Blitzer shared a laugh when Cooper called the demonstrators “teabaggers.” That was demonstrably the first time we were called that, so the term was not coined by Tea Partiers, but by Anderson Cooper.
Proof enough?
Not really. Doesn’t prove that TEA Partiers weren’t using it first, ignorant of its gay connotations.