Leviticus 5:8-9

MSB(i) 8 He is to bring them to the priest, who shall first present the one for the sin offering. He is to twist its head at the front of its neck without severing it; 9 then he is to sprinkle some of the blood of the sin offering on the side of the altar, while the rest of the blood is drained out at the base of the altar. It is a sin offering.