In a large mixing bowl, whisk the sweetened condensed milk and water together until well combined.
1 (14-ounce) can sweetened condensed milk, 1 ½ cups ice-cold water
Add the instant pudding mix and continue to whisk together until the mixture is smooth and creamy.
1 (3.4 ounce) box instant vanilla pudding mix
In another mixing bowl, beat the heavy cream until stiff peaks form.
3 cups heavy cream
Gently fold the freshly whipped cream into the pudding mixture until well combined.
In several plastic cups with lids or ramekins with lids, arrange a layer of vanilla wafers, followed by a layer of sliced bananas, and then a layer of the pudding mixture. 1 (11 ounce) box vanilla wafers, 4 ripe bananas
Repeat the pudding layering process until all of the ingredients have been used, making sure to end with a layer of pudding on top.
Cover the cups or ramekins with their lids and refrigerate for at least 4 hours or overnight. Or wrap the cups tightly in plastic wrap and freeze.
You can serve the cups frozen or allow them to thaw in the refrigerator before serving.