This phase mainly seems to be used by white adolescents and similarly complected college boys. What is the origin of this this somewhat iconic phrase? is it morphing into the meaning cited by the last definition cited below.
Pimp Hand
There’s a June 1999 post on Google Groups attibuting it to Snoop
It is the hand you use to control the sex workers who work for you by physical violence. Metaphorically, of course.
matt_mcl, I think that’s the literal meaning. I would guess that the metaphorical meaning is to be shrewd, smart and confident in your personal and professional dealings.
I first heard it on a “This American Life” show on NPR. It was an ex-pimp talking about his days in the biz. As mentioned above, it means keeping your girls in line.
Like most things relating to pimps, it has a certain ugly, disagreeable stupidity to it.
Not that there’s anything wrong with that.
Oh, wait. There is.
During my stint as a cab driver, I had the privilege to encounter several pimps and their victims. So, I consider myself fully qualified to say, with no further cite, that anyone who uses the name, image, idea, concept, etc. of “pimp” in any context except derogatory is totally and completely full of shit and is conspicously wallowing in their ignorance.
Tully Mars is correct, of course. However, Santa Claus and the Jolly Green Giant always keep a strong control over their HOs. I wouldn’t dream of dissing either the big red man or the big green man. Whirred.
Except when the pimp is Sweet Jimmy! 
Misogynistic and abusive manipulation of women. Very charming. I love how “pimp” and everything associated with it has somehow taken on positive connotations in pop culture.
Pimps are the scum of the earth, and those who aspire to be like them in any way are idiots. Tully is right on the money.
Hear, hear. I hate the glorification of everything that is “pimp”. Including children’s Hallowe’en costumes, for love of Pete. It’s wrong.
My bolding.
Like it or not, the positive connotation with the word “pimp” is most likely going to continue for some time.
Furthermore, I would interject that some may consider males who exploit sex workers to be “scum” but at the same time pimps do have several characteristics which are worthwhile to possess such as self-confidence, charisma, strong business sensibilities and outlandish and flashy dressing patterns. To generalize that anyone who would want to possess any of these characteristics and to be like a pimp to be an “idiot” is a foolish statement.
You know, I’ve actually had fantasies about being that kind of pimp. (Since I have absolutely no moral objections to prostitution as such, but much to the kind of men you’ll usually find running it.) I would treat the ladies with the respect due professionals, take only a small slice of their earnings, try to keep them off (at least the worst kinds of) drugs, have them regularly examined by an OB-GYN, at the company’s expense, and try to help some of them find other lines of work. (Some women can be happy in The Life, some turn to it only because they can think of nothing else to do; but it need not be so.) And all I would get in return would be a modest income and an unlimited supply of free services! Heck, if I were Catholic, the Church would probably make me the patron saint of prostitutes!
Of course, IANOtough guy, and for the regrettably necessary physical enforcement against abusive or deadbeat clients I would have to hire a tough guy . . . who would probably kill me and take over the operation . . .
Gimme a break. Does no one have a sense of irony? Careful you don’t throw your back’s out with all this knee-jerking.
You can have all that and not make a positive archetype out of someone who cold-heatedly controls women in an abusive and often physically violent way, and exploits them at their most desperate times. I mean, shit, how did people in the 1860s express their aspirations of self-confidence and charisma? How did young men in 1950 convey that they intended to be successful or stylish? When people throw around the word “pimp” casually they’re forgetting what a pimp actually is: scum.
You might call it knee-jerking, I personally call it good taste. There’s a lot of crude stuff that I’ll laugh at, but I don’t find anything ironic or entertaining about what a pimp represents. Sorry.
Somehow I don’t think those that commonly use that word are enjoying the irony of it. I’m not gonna have a fit over it, but I’ll still agree it’s a very stupid trend.
Oh and to answer the question (sorry about the double post), I always assumed that it meant the hand you use to “smack your hos”, to keep them in their place. I remember watching a Snoop Dogg video where he raised in hand as if he was about to backhand slap someone as he sang “keep your pimp hand strong”.