The Messenger of Allah ﷺ saw a donkey branded on its face and disapproved of it. He said, "By Allah, I will not brand except on the furthest part from the face." So he ordered his own donkey to be branded on its haunches, and he was the first to brand the haunches.
ورأى رسول الله ﷺ حمارا موسوم الوجه فأنكر ذلك، قال: فوالله لا أسمه إلا في أقصى شيء من الوجه، فأمر بحمار له فكوي في جاعرتيه، فهو أول من كوى الجاعرتين.
Muslim narrated it in Kitab al-Libas wa al-Zinah (2118), from Ahmad bin Isa, who said, Ibn Wahb told us, Amr bin Harith told me, from Yazid bin Abu Habib, that Naim Abu Abdullah, the freed servant of Umm Salama, told him that he heard Ibn Abbas say what was mentioned.His words, "the two jairatan," refer to the two fleshy parts that flank the base of the tailbone.