|1.||Down Low Brother|
A married man who turns into a bisexual by having anal sex with men outside of his marriage.
Alex got married and a year later turned into a down low brother.
|2.||down low brother|
a male who is hetrosexual but have sex with other men on the side.
Did you know that Bill is a down low brother, because Jack told me they been having sex for about a year now.