This hand gesture is supposed to look like a snake or lizard. There are multiple variations, where the pinkies are used as a tongue vs used as a tail, but the main concept is that it looks like a reptile
My informant learned about it in elementary school. It was way to differentiate who was “in the know or who was not”, sort of as cool thing you could do with your hands. However, the hand gesture was not exclusive, in that if someone didn’t know how to do the gesture they would be taught.
I recognized this hand gesture as it was something I used to do in my childhood despite being us growing up 4 years apart and across the country. Much like my informant, for my childhood it was used as something cool you can do when you were bored and it wasn’t ever withheld from others.