Leviticus 3:8-9

8He is to lay his hand on the head of his offering and slaughter it before the Tent of Meeting. Aaron’s sons are to splash its blood around on the altar.

9From the sacrifice of fellowship offerings he shall bring a gift made by fire to Adonai. Its fat—the entire tail fat cut away close to the backbone, along with the fat that covers the innards and all the fat that is on the entrails,