Mix 3½ cups of the milk with the pudding mixes.
Beat the pudding mixture with a wire whisk for 2 minutes until it is well blended.
Let stand for 5 minutes.
Fold 1 cup of the whipped topping into the pudding mix.
Arrange a layer of wafers on the bottom and sides of a 2-quart serving bowl.
Drizzle 2 Tbsps. of the remaining milk over the wafers.
Add a layer of banana slices and top with one-third of the pudding.
Repeat layers, drizzling wafer layer with remaining milk and ending with pudding.
Spread the remaining whipped topping over the pudding.
Refrigerate for at least 3 hours before serving.