It applies to a particular style of piano music, often played on a slightly out-of-tune piano.It could be used more generally to refer to the type of person who plays or likes such music.
I'm not sure of the actress your talking about, but i was wonder the same thing about one particular actress in that video and was able to find out the name of the main group of girls that danced in...
It's on Trace Adkins' 2005 album "Songs About Me"; the "video mix" of the song appears on his 2006 album "Dangerous Man." The song is also on the compilations, "Greatest Hits, Vol. 2: American Man"...
An excellent question! I have a plausible theory that allows for people hearing things diffently and words becoming corrupted. the phrase was first popular with broad summer areas such as beach...