In a medium bowl, whisk together sweetened condensed milk and ice cold water until smooth.

In another bowl, combine instant vanilla pudding mix with the condensed milk mixture and stir for 2-3 minutes until thickened.

Whip the heavy cream in a mixer until stiff peaks form, about 3-5 minutes.

Fold the pudding mixture into the whipped cream gently until combined.

Layer the pudding mixture, vanilla wafers, and sliced bananas in a large bowl, repeating the layers.

Cover with plastic wrap and refrigerate for 4 to 6 hours before serving.