Googled it, it's a Mean Girls thing, kinda wholesome to see such fandom around such an arbitrary date that was just mentioned
So funny how you can immediately see who's bothered to read the post by the questions they ask which have been answered in the post, in this case not only in text but with a gif as well :D.
LanternLight83 on the side there didn't just not read the post, he searched for what was being discussed to get the context. As opposed to, you know, clicking on the post and reading the first two sentences.