In your mixer, beat sweetened condensed milk and water for a minute or so, and then add the pudding mix and beat for two more minutes.
Transfer to a smaller bowl, cover, and refrigerate for at least 4 hours or overnight.
In a large bowl on medium speed, whip the heavy cream until stiff peaks form. Using a rubber spatula, gently fold in the pudding mixture until combined.
In a large bowl, or whatever you choose to serve your pudding in, layer the wafers, bananas, and pudding. Cover tightly with plastic wrap and refrigerate for about 8 hours before serving.
Recipe by pretty plain janes at https://prettyplainjanes.com/2014/01/22/mini-banana-puddings/