We called it the "Whammie Game"
For those unfamiliar - you make this hand sign, below your waist - and if the other person looks at it, it's a whammie....like a point (when I was a kid, you got punched if you looked).
The person looking has a brief opportunity to reverse it, if they can put a finger into the hole.
That's it - that's the whole game. It's dumb, but when you're a kid (of if you have brothers who you've been playing with for 40+ years)....
It's also the international dive sign language gesture meaning "I'm OK, are you OK?"
https://www.sportdiver.com/scuba-diving-hand-signals-every-diver-should-know
That dive sign has been around a lot longer than the reddit white power hand sign hoax.
https://www.adl.org/blog/how-the-ok-symbol-became-a-popular-trolling-gesture