A method of forming, filling, and sealing a flexible pouch with a guide pocket includes the steps of forming the pouch, and forming a first crease and second crease in the pouch that each projects outwardly and extends longitudinally from the upper edge, tapering in the direction of the lower edge. The method further includes the steps of opening and filling the pouch with the product and closing the pouch by sealing the upper edge transversely through the guide pocket, such that the first and second crease is eliminated as the upper edge is sealed.