An abbreviated form of the word belling.
To walk like a gangster.
To swing one's arms behind one's self in an exaggrerated fashion from left to right as one walks; resembling a bell swinging from side to side.
"See, I don't give a fuck 'cause I keep bellin',
Yo, what the fuck are they yellin'?"
-N.W.A. "Gangsta Gangsta"