The sponge cake batter should be divided into prepared pans and baked immediately or the air bubbles will start to break.  Pans should be buttered and floured using a combination of four parts melted butter to one part flour, by volume.  By brushing this mixture on the pans you only have to handle them once.  With some lighter mixture, such as two-way or chiffon, it is advantageous to butter and flour only the bottom of the pan or line it with a circle of baking paper, allowing the sponge to stick to the sides and thereby preventing it from shrinking as it bakes.