A beverage container for mixing a beverage is disclosed. The beverage container includes a cup having a stirring flap integral to an internal side wall of the cup. The stifling flap has a sine wave shape and comprises a top fin protruding near the top of the internal wall and a bottom fin protruding near the bottom of the internal wall of the cup. The top fin and the bottom fin are separated by a central portion. The cup is swirled in a circular motion by a person's hand to mix the liquid contained within. The central portion allows liquid to pass freely through the middle of the cup to gain momentum when the cup is swirled. The bottom fin has the shape of a lower case letter ‘h’, to allow solid material gathered in the bottom of the cup to pass underneath the bottom fin and mix with liquid.