“When white married men have sex with other men, society is quick to offer explanations of their individual behaviors, she said. But when black men do the same thing it’s seen as a social problem plaguing black communities.

The historical context of the down low is baked into the black cultural experience, added McCune. “It comes from trying to keep things secret when under high surveillance, when in slavery. I can read, but I have to keep that on the DL, so I don’t get lynched,” he said, elaborating on the historical parallel.

Davis agreed with that connection. “As black people began to push for civil rights, one of the things we became sensitive to was, ‘How are our bodies perceived?’” said Davis. “You see a continued policing of the black body. We had to make sure our bodies were respectable and controlled.”

The down low, then, he argued, is yet another way to stigmatize black men’s bodies.”

This quote, taken from a larger piece by the Washington Post discusses the practice of bisexual behavior in African American men.

The term, also called “DL” is defined by Urban Dictionary as “The Down Low, like many terms and phrases in the American culture, can attribute their genesis to the Gay and Urban Black community, The, "DL" has evolved to be used universally to refer to activities conducted secretly and behind the scenes. The DL can also refer to behavior described as slick or deceptive.
The Term has truly evolved from being used to describe convert male homosexual behavior of a man Fronting (portraying himself), as a heterosexual and in relative is actually a closet Gay man to now refer to any behavior, action, or behavior that can be described as secretive or deceptive.”

To outsiders, this is a pejorative term. But for those in the know it is a desriptor that defines a certain ‘type’: straight acting/straight appearing.

There are terms used in the white community that have similar connotations, but without the stigma that has become associated with the down low: most notably bisexual, trade, rough trade.

https://www.washingtonpost.com/national/religion/why-some-black-men-prefer-the-down-low-and-what-it-says-about-the-black-church-in-america/2015/09/04/59788754-533b-11e5-b225-90edbd49f362_story.html