"Now every since I could remember I been poppin my collar
Every since I could remember I been working this hoes And they betta put my money in my hand" -- Three 6 Mafia
That's urban slang for pimpin', stunnin', or lookin' fly made popular by the rap group 3 six mafia. Or if someone wants their respect or recognition for doing something. Kind of like when the Fonze on 'Happy Days' use to turn his collar up to be cool.
A phrase generally used in the hip hop lexicon. It describes not only an action, but also a general attitude. The term was originally used in this sense by the rapper E-40. When used by E-40, and many other hip hop artists including Three 6 Mafia in their song Poppin My Collar, the term refers to the act of pulling one's collar, or the clothing where one's collar would be (as when wearing a t-shirt), with the thumb and fingertips. One then releases the clothing in varying degrees of flamboyance. Used in this sense, "poppin' ya collar" is more about the attitude and message of confidence portrayed in so doing than any clothing style (see upturned collar). E-40 immortalized the term (and the accompanying attitude), in his song Pop Ya Collar from his album Loyalty and Betrayal.
1. After you get your car officially pimped, xzibit will be poppin' ya collar.
2. Never confuse the international sign for welling with poppin' ya collar.