I found this picture of what I believe as hip hop clothing. Like the person that posted it, I also wondered why these pants are worn this way. There must be a reason why. That sketch at the right could be the reason? It was truly, truly hilarious to me!
Hip hop clothing is also one of those streetwear clothing. This fashion originated in some parts of the US (New York City, Los Angeles, Chicago, Philadelphia, San Francisco Bay Area, to name a few) by African American youth. This comprises the hip hop culture that had changed significantly as time passed by. One can search via Wikipedia to know more of the history.
This kind of culture, music and clothing had already reached the Philippines and you can see some young boys (and a few girls) donned in this attire.
I thank God my son did not like this fashion a bit.