In a large bowl, whisk together the pudding mix and milk until smooth. Add sweetened condensed milk, sour cream, and vanilla. Stir until well combined. Fold in cool whip until well incorporated and smooth.

Reserve 12-14 vanilla wafers and 6 banana slices for garnishing. Cover the bottom of a large serving bowl with some vanilla wafers. Cover the wafers with 1/3 of the remaining banana slices. Scoop 1/3 of the pudding mixture over the pudding. Repeat layers with 1/2 of the remaining vanilla wafers, half of the remaining banana slices and 1/2 of the remaining pudding mixture. Repeat layers again with remaining vanilla wafer, banana slices and pudding mixture. Garnish with the reserved vanilla wafers (some crushed) and banana slices.

Let set in the refrigerator for at least 30 minutes or until ready to serve. Pudding keeps well covered with plastic wrap in the refrigerator for about 5 days.