I don't think it is regional. I don't know that though.

my brother and his friends used to say it.

our other dog terms like sea dog, salty dog, and cappy dog. LOL

of daring, double daring, double dog daring etc

We used that phrase often.

I didn't hear growing up in Atlanta.

And that's different regions of one state.

State to state and multiple regions would yield "old sayings" not everyone was familiar with...most likely a result of who did the settling of the area as well as who was moving in and out of neighborhoods.

I grew up hearing phrases that I thought everybody in the state knew. Then I moved to Atlanta and people would ask "WHAT?"

And then I met someone from Mississippi...

language.

True all over. Different regions. Different patterns of speech, idioms, and shorthand of speech.

I always found it interesting. Fascinating, even.

Language tells a story.

Next time I heard it was in the movie, Pulp Fiction.

My cousins in TX used this phrase too, I believe.

Double dog dare is a term that has been in use since the mid- to late 1800s, though it experienced a renaissance in the 1980s. We will examine the meaning of the term double dog dare, where it came from and some examples of its use in sentences.

https://grammarist.com/phrase/double-dog-dare/

I could never turn down a double dog!

n/t

I grew up in south Georgia. I still use both phrases from time to time.