Leviticus 8:23-24

After it had been slaughtered, Moshe took some of its blood and put it on the tip of Aharon's right ear, on the thumb of his right hand, and on the big toe of his right foot.

Next Aharon's sons were brought, and Moshe put some of the blood on the tips of their right ears, on the thumbs of their right hands, and on the big toes of their right feet; then Moshe splashed the blood on all sides of the altar.