In the booklet that comes with the KC & the Sunshine Band boxed set, Harvey Wayne Kasey said that the dance known as "the bump" was really popular in 1975. While talking about how this dance made the "booties" of young female dancers shake like Jello, his band wrote the song "Shake, shake, shake, shake your booty". It was released May 27th 1976 and it soon became the third Number 1 hit single by KC & the Sunshine band on the Billboard Top 100 chart. I can not get any of the links to the half dozen You Tube videos for this song to work. However, just because I am to inept to provide the easy to click link does not mean you should not go to You Tube and search for "Shake, shake, shake, shake your booty" by KC and the Sunshine band. It is one of the classic disco songs of the mid 1970s.

Im not a historian but the earliest instance that comes to mind is "shake your tail feather" by the du tones or something. Its from 1963