Preheat oven to 350 degrees Fahrenheit.

Follow directions on the box for the cake mix.  Bake as directed.

While cake is baking, whisk the three milks together in a bowl.

While the cake is still warm, poke holes in the cake with the back of a spoon or the tines of a fork.  Poke them about a 1/2 inch apart.  

Pour the milk mixture slowly over the cake, allowing milk to be absorbed.

Refrigerate until completely chilled.

Beat the whip cream, sugar and vanilla together until stiff.

Spread whip cream on top of the chilled cake.  Return to the refrigerator until ready to serve.