Flip-Up Day in your elementary school?
I remembered suddenly the "names" we gave days of the week in elementary school today. I was talking about the "Hump Day" camel, and how we thought "Hump Day" was something sexual. And I remembered that Friday was called "Flip-Up Day".
Some students would flip up the dresses of any girls on a Friday. It was one of those things that probably wouldn't go over too well these days, probably end up with a 6 year old being suspended and charged with sexual harassment and it making a round on social media.
This was something like... 25 years ago in South Carolina, something around 2nd grade? I don't recall it being known in Michigan once I entered Junior High.