Leviticus 4:25-26

25Then the priest must take some of the blood of the sin offering with his finger and put it on the horns of the altar of burnt offering, and he must pour out the rest of its blood at the base of the altar of burnt offering.

26Then the priest must offer all of its fat up in smoke on the altar like the fat of the peace offering sacrifice. So the priest will make atonement on his behalf for his sin and he will be forgiven.