Donkey Does Dallas, also known as the Muff and the Mule, is a series of adult magazines written by El Burro. The magazines were published in 2001 and sold at the XXXMags store in the Red Light District of Liberty City. The magazine is released monthly and, as of the mission Big'n'Veiny, had three volumes released.
During the mission Big'n'Veiny, a criminal under the influence of SPANK steals the volumes. El Burro sends Claude to retrieve the magazines and then deliver them back to the XXXMags store. Following this mission, Claude can find a stack of the magazines outside the Portland Safehouse.