"My mans and 'em" is a more recent of urban phraseology, made popular by the prolific rapper/actor DMX (Dark Man X). It means "my friends."
See why my "mans and 'em" call me the Benjamin Banneker of the 20th and 21st
by bobo February 21, 2003
The name guys give for their penis and balls.
Hey baby, you wanna meet my mans and 'em?
by Krazee 8 May 19, 2005