Faith Bacon dances around wearing a tiny, spangly thong bikini (it wasn't called that back then), obscuring the details with a big piece of sheer black cloth in this soundie.
Soundies were short films, usually about three minutes in length, meant to be played on a sort of musical jukebox called a Mills Panoram. Usually you got a song performed by a singer or group which might later become prominent; Doris Day got her start on screen in soundies, as did Dorothy Dandridge.
Not all of them were songs. There were comedy acts, and burlesque acts like this one; Mills had intended them to offer a variety-show-like assortment. Since the majority of the devices were located in bars and night clubs, this looks appropriate.