The term "ninja" has apparently taken on another meaning in modern culture. It seems to be equated with "pimp," a quite different syntax from its feudal Japanese origins.
From Mother Jones, a chilling story written by an incarcerated girl about her experience as a prostitute:
...I tell him, "Please. I'm only 15, let me live." He comes…I think to myself, only the devil would do such a thing. I look into his eyes trying to cut into his soul and leave a scar forever. The handle to his gun hits me upside my face. Everything is black when I hit the cement and then I wake up from the cold weather. I hear his car door slam. I try to get up but my legs feel loose and my head is spinning. I lean against the car, look into the car window and see that my face is swollen and my eye is black. I thank God to be alive.
I called "my ninja," and he asks me how much money I got. I say, "I just got raped" and he says, "Are you okay?" I say "Do you care?" and he says "Bitch…" I hang up in his face…and I've been pimp free ever since.
To all girls out there who prostitute, get out while you can. You are ruining your body and soul...eventually everything will catch up to you like it has to me. I'm 18 now with sorrow in my heart and shame. I am bruised and scarred forever. If you do what you do, do it the right way, and the most safe way…praying for you.