Prepare the Base
In a large mixing bowl, whisk together the instant vanilla pudding mix and milk until smooth and thickened.
Fold in the Whipped Topping
Gently fold the whipped topping into the pudding mixture until fully combined and fluffy.
Add the Mix-Ins
Stir in the drained crushed pineapple, shredded coconut, mini marshmallows, and any optional ingredients like cherries or nuts.
Chill the Fluff
Cover the bowl with plastic wrap and refrigerate for at least 2 hours to allow the flavors to meld together.
Serve and Enjoy
Spoon the Pina Colada Fluff into serving dishes or a large serving bowl. Garnish with extra shredded coconut or cherries if desired.