alligator role

Something performed in jail or prison to kill oneself. You tie a towel to the bed and roll it up around your neck on the floor. By the time it's so tight it's choking you, you won't have room to escape & will surely die. A very common way people kill themselves in prison.

"Damn. Did you hear about Mark? She killed herself in her cell last night. Did an alligator role & choked out"