Take your son and do a Google image search of:
prison bitch pants
And see how many pictures like this come back.
sagging
wearing ones pants around the hips so that they sag down and bunch up around the ankles. Originally, this was a prison thing that signified that you were another prisoner's property, ie bitch. Punks were forced to wear their pants this way so it would be easier for their masters to pull their pants down and butt-f__k them. Somehow this became a 1990's fashion trend. I learned this from watching a TV special on prison life. The inmate who related the story was an elderly black gentleman who had been sentenced to life in prison and had been there for over fifty years. He marveled how such a mark of shame became a fashion statement. He said that younger inmates don't believe him when he tells them but swears it's the truth. I believed him. I also think they should let him out already, he's like 80 and I don't think he represents a threat to society.
urbandictionary.com-Prison Bitch Syndrome
Prison Bitch Syndrome
Prison Bitch Syndrome (or P.B.S) originated in prison and was done when a prison bitch would pull down his pants half way to expose his boxers (low riding). This told other guys that he was avaliable.
Next, check out this link
urbandictionary.com-prison-bitch
This will give you MANY definitions of urban slang that deal with being a Prison Bitch.But be forwarned, this is an URBAN dictionary, and the language IS VERY RAW.
Lastly, do a Google search of:
Prison Bitch
Both search and image. The image search will have some EXTREMELY graphic images.
One more thing. Urban Dictionary has some merchandise that you can buy.
http://www.urbandictionary.com/products.php?term=prison%20bitch&defid=455209
Maybe a nice refridgerator magnet
A little mocking might go a long way.