taken from one forum:
Well, now I learned all the details of wearing pants under my ass.
I knew a long time ago that the fashion of wearing pants so low came from American prisons where prisoners are prohibited from wearing a belt. How low should I drop my pants? It turned out that how low the pants sit is determined by how much a prisoner wants and is willing to enter into, to put it gently, a close relationship with another prisoner. Since it is impossible to talk about this with supervisors in public places outside the camera, they have come up with this method of delivering signals to each other. The lower the trousers, the more ready and willing he is. Then this fashion went into normal life. So guys, pull up your pants, bleat!