We have that fashion craze in the UK as well,now that we know of the origin,,can someone explain,,,
What stops them from falling down to their ankles,when my trousers/pants get past my butt cheeks,they drop straight to the floor.

Pitbull
The next one you see, look at his/her thumb and a loop on the pants. They are connected together.
Most wearers however, do have a belt on and just cinch it hard to keep the pants from exposing the jewels and dropping to the ankles.