What is a period sign?

No, not that. (I hope.)

If they thought that I shouldn’t do ‘The Griddy’ across the stage and do the Girls’ High traditions, nobody should have been able to wave or blow kisses or do period signs because I feel like that’s the same thing. I feel like that’s unfair," said Abdur-Rahman.

She probably said periodt sign. It’s slang for “full stop” or “absolutely”. Reporter probably didn’t catch the nuance.

In other words, other students were doing a periodt sign as in, a gesture that means “it’s over.” Probably the one I’ve usually seen called a “throat slash” gesture.

I haven’t seen any video, but this is most like exactly it.

Hmm. Would that really fit at a graduation? I always took that sign as saying either “stop!” or “this sucks.” The context makes it seem like the period(t) sign is a celebration.

The particular attitude coming to mind for me is when an athlete does something good in a game, and then does the gesture I’m thinking of to indicate to everyone “that’s it, game over, we’re done here.”

I think it fits, in the sense of “the end, it’s over, period.”

Hmm. I don’t watch sports much. Do you know of any examples that might have clips?

https://www.youtube.com/watch?v=DM-J-5G6xIA

To explain the video title, the gesture was banned by professional and college football and basketball leagues about 25 years ago for PR reasons, related to players doing bad things off the field.

Ah. Doesn’t look negative to me. But it sounds like there is some controversy about it being offensive. Which all the more makes the point in the OP, if that sign is allowed, but dancing isn’t.

For the record, I did a little celebration gesture when I graduated high school. It was a joke I’d been doing for friends. After that point, others would do a quick gesture of celebration. It didn’t make anything take longer, and no one cared.

To be clear, from the article it seems officially the problem wasn’t the dancing but the cheering from the crowd. The students had been warned that cheering or applauding from their family and friends would result in no diploma being given, and that was the case here.