Leviticus 4:17-18, 25

Then the priest shall dip his finger in the blood and sprinkle it seven times before the LORD, in front of the veil. And he shall put some of the blood on the horns of the altar which is before the LORD, which is in the tabernacle of meeting; and he shall pour the remaining blood at the base of the altar of burnt offering, which is at the door of the tabernacle of meeting.

The priest shall take some of the blood of the sin offering with his finger, put it on the horns of the altar of burnt offering, and pour its blood at the base of the altar of burnt offering.