Musannaf Ibn Abi Shayba 35:29

Waki’ narrated to us, from Hisham al-Dastawa’i, from Qatadah, from Abu Hassan, from Ibn Abbas, that the Prophet (peace and blessings of Allah be upon him) performed *ish’ar* (marking the sacrificial animal) on the right side, and he wiped the blood with his hand.