It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) would make his mount kneel crosswise, then pray facing it. I said: When the camels had gone off, what would he do? He said: He would take the saddle, set it straight in front of him, and pray facing its back-rest.
(b) Another narration adds that Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) also used to do this.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3459