It was narrated from Ibn ‘Abbas that the Prophet (ﷺ) marked the sacrificial animal on the right side of the hump and wiped away the blood
Hadith No. 3097
Sunan Ibn Majah
Gradings:
Al-Albani:
Sahih
Muhammad Fouad Abd al-Baqi:
Sahih
Shuaib Al Arnaut:
Sahih
Zubair Ali Zai:
Sahih Muslim