Season the cavity of the turkey with salt and pepper and fill the cavity with the, lemons, garlic and onion. Gently lift the skin of the turkey by using your fingers and going in between the skin and body of the bird. Rub half of the compound butter under the skin of the bird, spreading some of the butter on top of the skin as well. Take the remaining butter and melt it over the low heat on the stove or in the microwave. Dampen your cheesecloth with warm water and squeeze dry. Submerge the cheesecloth into the melted butter, making sure all of the cheese cloth has soaked up the butter. Lay the cheesecloth over the bird, covering most of the bird. Drizzle any remaining butter over the turkey.