Mishkat al-Masabih #723

Nafi’ said on the authority of Ibn ‘Umar that the Prophet used to make his riding-beast kneel between him and the qibla and pray facing it. (Bukhari and Muslim.) Bukhari added that Nafi' asked Ibn ‘Umar, saying, “Tell me what happened when the camels moved away,” to which he replied, “He used to take the saddle, put it straight, and pray facing the back of it.”