The term is thought by many to be originating from Black American Vernacular English, namely from the 1920’s, with the rise of black female blues artists, like Bessie Smith.
During the era, being a lesbian was more of a taboo for women, though bisexuality was more accepted by society.
We may see how the acronym was utilized to maintain secrecy in a culture still filled with prejudice against women and black people and especially against black women.
With the rise of the LGBT movement, the term became more and more embraced, though it is nearly not as popular as the other words referring to lesbian or bisexual women.
Today we may find the expression mostly on sites where people discuss sexuality, such as Tumblr.
The first Urban Dictionary entry on the term was added in 2004, though it is arguably incomprehensible.
Nonetheless, there are several other definitions that have been added on the abbreviation over time.