My understanding is that they had the victim tied limb to limb by rope to 4 horses. A rope was secured tightly around the privates of the victim, and attached to a fifth horse, who walked forward to draw the entrails from the victim, who then got to watch them burn, if he survived.
THEN, the other four horses walk forward, ripping the body into quarter sections.
I used to have a photo from Iran/Iraq war showing this. they used four vehicles.
Ouch! That has got to hurt.
"Hanging, drawing, and quartering" was the traditional English punishment for high treason (as opposed to low or petit treason). William Wallace, a bunch of Catholic priests, and Guy Fawkes were hanged, drawn and quartered (although Fawkes escaped the worst of it by leaping from the ladder after the rope was placed, breaking his neck and dying instantly). The law remained on the books well into the 19th century, but was last applied to the Cato Street Conspirators - during the reign of George IV.