usually used as shut up or yea right.
Max: "hey marco, you should let me hit a 20 off ya till next week"
Expression of suprise.
When a friend axe's you something, and you were obviously going to do it, you state "Nigga-Please!" to express the shame you feel at having such an insult to your honor.
Lysol: We gonna rape some bitches tonight?
Tyrolla: Pass the blunt.