down low
Refers to when closeted black men leading mostly heterosexual lives seek other men for sex that is often anonymus and unprotected
Example:
"I am a black man who likes other men, but because of the stigma in the black community about being gay, I will only have sex on the down low."
"I am a black man who likes other men, but because of the stigma in the black community about being gay, I will only have sex on the down low."