Ziyad bin Jubair says that I was with Sayyiduna Ibn Umar (may Allah be pleased with them both) in the plain of Mina. On the way, he passed by a man who had made his she-camel kneel down and wanted to slaughter it. Sayyiduna Ibn Umar (may Allah be pleased with them both) said to him: Make it stand, tie its legs, and then slaughter it; this is the Sunnah of the Prophet (peace and blessings be upon him).
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 4459