Put these items into the freezer to chill for 10 minutes: a medium metal bowl, whisk and 2-cup carton of whipping cream. While this is chilling, in a large bowl, combine sweetened condensed milk and water. Add pudding mix and beat well with electric mixer and chill this mixture in the refrigerator for 5 minutes.
Remove freezer items. With electric whisk attachment, whip the whipping cream in the chilled metal bowl for 5 minutes. Fold the whipped cream into the bowl with the milk, water and pudding mix. Spoon 1 cup pudding mixture into a 2½-quart glass serving bowl. Top with ⅓ each of the wafers, bananas and pudding. Repeat layering twice, ending with the pudding. Garnish with vanilla wafers in any pattern and chill thoroughly. Best if made ahead the day before you want to serve it so the wafers get soft.