The phrase 'i triple dog dare you christmas story' could imply a Christmas story centered around a dare. For instance, perhaps there's a family gathering during Christmas. The cousins are all bored, and one of them says 'I triple dog dare you' to another cousin to do something like steal a cookie from the plate that's meant for Santa. And then the whole story could be about what happens next - whether they get caught, what kind of chaos ensues, and how they learn a lesson about respecting Christmas traditions in the end.
Well, 'triple dog dare' is a very strong form of dare in English slang. So it could be about a Christmas story where someone is daring another person in a really intense way. Maybe in the story, a kid triple dog dares his friend to do something really crazy during Christmas, like climbing on the roof to look for Santa.
I think it might refer to a Christmas story that involves a dare that is so extreme it's a 'triple dog dare'. It could be a story set in a small town during Christmas. There's a group of kids, and one of them is always coming up with these wild dares. This time, it's a triple dog dare about something related to a local Christmas tradition, like sneaking into the church to see if they can find the real Christmas star that's part of the nativity scene.