Of all the ordination rites, this one is the strangest. Moses slaughtered the second ram, and the Targum Pseudo-Jonathan on Exodus 29:20 tells us exactly what he did with the blood. He placed it upon the tip of Aharon's right ear, and upon the tip of the right ear of his sons, and upon the thumb of their right hands, and upon the toe of their right feet.
The Sages read the three points as a curriculum. The ear, because a priest must learn to listen before he rules. The thumb, because the hand will offer, lift, and sprinkle — and every act must be measured. The foot, because the priest will walk between the altar and the curtain, and the path itself must be consecrated. Blood on these three points meant: whatever you hear, whatever you handle, wherever you walk, it all belongs to God.
The right side matters too. In the Sages' geography of the body, the right hand is the hand of strength, the right ear the ear of attention. Aaron was being dedicated not in his whole body at once but at his strongest points — as if God were saying, I am not asking for your weakness. I am asking for the best of you.
The takeaway is severe and beautiful. Ordination was not a title handed down at a ceremony. It was three small marks on three small surfaces of the body, and from that moment forward the priest's best listening, best work, and best walking were no longer his own.