Of course your Flexi-Kiwi ( https://www.printables.com/model/497594-flexi-kiwi-articulated-kiwi-bird) needs a santa hat!
Print the hat on its side - with support - and simply push it on to the head of the kiwi! :-D
A filament change from red to white will make it much more festive, but some white correction fluid or regular paint will also do the trick.
Don't be too ambitious when you remove the support - if you scrape or file too much, the hat may be too loose.
P.S. Want a royal flair for your flexi-kiwi? Check out the royal crown here: https://www.printables.com/model/498347-royal-crown-for-flexi-kiwi
The author marked this model as their own original creation.