A practice in prison when prisoners arrange the three-high bunk beds in a rough square and drape them with blankets to block off the view of the guards. It is in the middle of this that a gang rape can continue for an astonishing amount of time. Guys beaten and dragged into the covered wagon are set upon by dozens of men. They have all their teeth knocked out, they are forced to perform fellatio for hours and hours while being savagely anal raped until their assholes literally gush blood.
An overcrowded room like this quickly becomes host to what is known as the covered wagon. Avoid them at all costs.