The ritual was as much a part of the confession as the act itself. The confession was for God; the ritual was for to prepare the confessor and priest both for what was to come.
At least, that was how Peter thought of it.
"I am listening, my Son," Peter responded. Confession was an Act of Anonymity. It was a time to wield the Power granted to him by the Lord and by Society, to act as God's voice and to comfort those whose sings were so great that the confessor could never speak of them aloud anywhere else. This was the Job part of his profession -- he preferred the quiet, personal chats to this. But it was necessary, and Peter was willing and able to shoulder the burden of it.