Volume 2, Book 20, Number 202:
Narrated ‘Amir bin Rabi’a,
I saw the Prophet on his Mount praying Nawafil by nodding his head, whatever direction he
faced, but Allah’s Apostle never did the same in offering the compulsory prayers. Narrated Salim: At
night’Abdullah bin ‘Umar used to offer the prayer on the back of his animal during the journey and
never cared about the direction he faced. Ibn ‘Umar said, “Allah’s Apostle used to offer the optional
prayer on the back of his Mount facing any direction and also used to pray the Witr on it but never
offered the compulsory prayer on it.”