Larding is where you insert fat into the meat or under the skin, like flavored butter under the chicken skin. This is what I do when cooking chicken as it stops the breast meat from drying out. You could inject aromatic fats or oils into the flesh of the meat before roasting.  This will also act as a marinade. Barding is where you cover meats with fat, like covering turkey with bacon or covering lean beef with pork fat before roasting.