What are some words you've heard, other than cheese, that prompts a smile when getting your photo took?

Nine-Eleven!

https://petapixel.com/2018/11/20/tips-for-getting-kids-to-smile-naturally-in-photos-10-secrets-from-a-pro/

Boobies!

Provocateur.Yeah, that’s it. yawn

I see this question provoked a mammoth response.
I shall deal with the flood of contributions as swiftly as possible & be operating a queue system.
Be patient patrons, your turn will come.

Kikaha!
Hawaiian name for bird and the name of my outrigger canoe club.

Also Tenshinhan’s signature attack.

“Pepperoni pizza”, just gets the corner of the lips up.

Anyone saying “getting your photo took” makes me smile.

That and “ucme”.

“congratulations. You won a million dollars”

Someone told me to say “oral sex”. I blushed and giggles. It worked, so the next time I took a picture it was of my mom, and I gave it a try.
It caught her off guard, and she laughed. It was the only picture ever takes of her that didn’t look plastic and posed. In every other picture she would have her hands at her sides. When a someone tells her to say cheese, her fingers flick up on both hands zero like little baby chick wings. A stock smile pops onto her face, and her head would tilt slightly.
I was proud of my successful grab of a real expression.

Ah1…Ahh2…& Ahhh 3

“Okay, everyone smile and say SHIT”.

We used to have a president of my company named Mr. Glasscock. It makes me giggle every time I hear the name, because apparently I’m actually a 12 year old boy in real life.

I often say “Say sex”. The word “sex” makes the mouth smile much like cheese does. IF it doesn’t, it makes everybody giggle or laugh giving me the same result!!!

@chyna, lol, there’s so many ways to go with that.
A group of 12 year old boys, and an extra large pizza would make it a razz party for an hour.

“Spaghetti!” During my early years of grammar school, the photographer had us say this for our annual class photo. It worked; those pictures show groups of laughing, happy-looking kids.

“Prunes” is used by some models and actresses to get a semi-pursed look. Try it in a mirror, and you’ll see something between a real smile and that silly, exaggerated duck-face that was all the rage a few years back.