Blend milk and vanilla pudding packets for about 2 minutes. Fold in Cool Whip.
In a 9x13 pan, layer graham crackers to cover entire bottom of pan. You may need to cut and shape the crackers to fit.
Pour half of the pudding/cool whip mixture on top and level.
Put another layer of graham crackers to cover entire surface.
Put the second half of pudding/cool whip mixture on top and level.
Put the final layer of graham crackers on top with bumpy side down. This will help the top look more smooth when you go to put the frosting on top.
FOR THE FROSTING: Microwave butter and milk just enough so that they are melted together. You do not need to boil it. Add cocoa and powdered sugar and blend together. This will be a runnier frosting/glaze. Pour over top of graham crackers and smooth out nicely.