First spray the bottom of a 9 x 13 pan with non-stick spray then put down a single layer of graham crackers (you may have to cut them to fit)
Next mix the pudding and milk, when it starts to thicken fold in the Cool Whip
Spread one half of the pudding mixture onto the crackers then add another layer of crackers (repeat)
Frost the top layer of crackers using all of the icing
Refrigerate overnight or at least four hours