Leviticus 3:8-9

8and he shall lay his hand on the head of his offering and kill it before the Tent of Meeting, and Aaron’s sons shall sprinkle its blood around on the altar.

9From the sacrifice of peace offerings he shall bring as an offering by fire to the Lord, its fat, the entire fat tail which he shall remove close to the backbone, and the fat that covers the entrails, and all the fat which is on the entrails,