You use this term whenever you see someone crushing or hitting on a guy. Usually in jokingly manner. You can either shout it while the action is taking place (example 1) or in a way where you're telling them to make the first move (example 2).
Example 1:
"Omg guys look over there!"
"Is that Jennie hitting on Kai?"
"(Shouts at Jennie from a distance) GET YOUR MANSGIRL!"
Example 2
Jennie: "What am I even supposed to say if I go up to him?"
Lisa: "Just go, you're worrying way too much. Come on girl, go get your mans"
Someone who is addicted to obtaining money and building wealth. A money addict and fanatic. Breadheads often work more than one full-time job, and some even participate in illicit activities to "obtain the bread".