In the video, a person is seen decorating a cupcake with white frosting. The cupcake is placed on a wooden surface, and the person uses a piping bag to apply the frosting in a circular motion, starting from the center and moving outwards. The frosting is applied in a smooth and even manner, creating a visually appealing swirl on top of the cupcake. The person's hand is steady, and the frosting is applied with precision, resulting in a beautifully decorated cupcake.