The Prophet ﷺ used to offer (Nawafil) prayers on his Rahila (mount) facing its direction by signals, but not the compulsory prayer. He also used to pray witr on his (mount) Rahila.  

كَانَ النَّبِيُّ ﷺ يُصَلِّي فِي السَّفَرِ عَلَى رَاحِلَتِهِ حَيْثُ تَوَجَّهَتْ بِهِ يُومِئُ إِيمَاءً صَلاَةَ اللَّيْلِ إِلاَّ الْفَرَائِضَ وَيُوتِرُ عَلَى رَاحِلَتِهِ