Whisk together the sweetened condensed milk and the ice-cold water. Using a hand held electric mixer, gradually pour and blend in one box of the dry pudding mix with sweetened condensed milk and the ice-cold water mixture until it is smooth. Cover the pudding mixture and refrigerate it for at least 3 hours. (it may be left overnight)
In a large bowl, beat the heavy cream until stiff peaks form. This will take around 3 minutes because it’s such a large amount of heavy cream. The cream will begin to thicken and get frothy, just keep beating on a high speed until set up and stiff. Blend in the vanilla extract.
Next, fold pudding into the whipped cream. Once everything is combined, add 5 tablespoons of dry vanilla pudding (from the second package)and beat until you get a fluffier consistency.
Assemble the dessert in a clear glass trifle bowl. Layer ⅓ of the pudding, ⅓ of nilla the wafers, and ⅓of the bananas. Repeat this again, then finish with a heaping layer of pudding. Make sure all of the bananas are completely covered or they may turn brown more quickly.
After assembling, chill for at least 4 hours to allow the vanilla wafers to soften up. Garnish with nilla wafers crumbs and sliced bananas as you are serving.