Leviticus 3:8-9

8And he shall lay his hand upon the head of his offering, and kill it before the tabernacle of the congregation: and Aaron’s sons shall sprinkle the blood thereof round about upon the altar.

9And he shall offer of the sacrifice of the peace offering an offering made by fire unto Yhwh; the fat thereof, and the whole rump, it shall he take off hard by the backbone; and the fat that covereth the inwards, and all the fat that is upon the inwards,