Here’s the news from winter break: Scrunchies have become a desired item for junior-high schoolboys.

Today’s tween girls are offering their scrunchies — the fabric-poofed hair elastics last popular in the 1980s — to their crushes. If accepted, the boy will wear it around his wrist until he finds a new scrunchie — er, crush.

If he really likes the girl, he can offer his hoodie in return.

“Well, now I know why my 13-year-old has a bunch of scrunchies in his room, and why his hoodie is missing,” said Amanda Marks, who lives in Decatur, Ga., and is the co-host and producer of the “Sis & Tell podcast.

How this trend started is a bit of a mystery, but it appears to have gained traction over the course of this accursed year, 2019.

It’s possible that the Netflix movie “To All the Boys I’ve Loved Before” had something to do with it. During the flick, which is based on Jenny Han’s young adult book series, the main character snags a scrunchie from his crush’s hair and puts it on his wrist, commenting that she looks pretty with her hair down.

Ms. Han had no idea it was such an influential scene.

“I had no idea kids were offering up scrunchies to their crushes,” she said. “I think it’s delightful.”

Perhaps adults are unaware of or indifferent to the scrunchie crush craze, but in junior highs and even in some high schools across the country, it appears to be quite a big deal.

The hashtag #Savethescrunchies trended briefly this fall, scrunchie collection funds started by parents of tween girls have started, and undoubtedly any store selling scrunchies is making money off these crushes.

And there are rules, according to Nora Cullerton, a 15-year-old in River Forest, Ill.

“If a guy is wearing a scrunchie, you know he has a girlfriend,” she said. “You can give any color, and the boys will take a Snapchat of the scrunchie and send it to the girl to show them that they’re wearing it.”

In middle school, Nora said, a girl gives a boy a scrunchie if she likes him. In high school, she gives it to him if they’re dating. If the couple is in a nontraditional relationship? Anything could happen.

You may note that, in a reversal of the pay gap, the scrunchie-hoodie trade is not an equal one.

After learning of the trend and noticing the scrunchies piling on her son’s desk — along with the missing hoodie — Ms. Marks told her son that it was ridiculous to give away a hoodie because it’s simply not equivalent in monetary value to a scrunchie.

“I mentioned I would totally buy him some scrunchies to give to girls he had crushes on if he wanted me to,” Ms. Marks said. “Of course he gave me a look that said, ‘You’re being ridiculous.’”

Ms. Mark, 42, said that back in her day they gave each other a mix tape or CD, or even homemade friendship bracelets made out of string.

“I’m guessing sending someone a Spotify playlist just doesn’t have the same sentiment?” she said dryly.

Kate Sorensen, the mother of a 12-year-old boy in Ankeny, Iowa, said the scrunchie crush trades are “running rampant” in his sixth grade class. He has arrived home with two so far.

“As for our son giving away a hoodie — he’s got plenty to spare, however I would be really frustrated if he started giving clothes away,” Ms. Sorensen said.

The two scrunchies he received now live on his desk in his room.

Other tweens are possessive over their scrunchies, given the fact that posh velvet or satin are the styles to get and they can really make a dent in the old allowance ($18 for a set of 10 at Urban Outfitters).

Tully Lovell, 10, a fifth-grader in River Forest, Ill., said she hasn’t give anyone a scrunchie and doesn’t plan on indulging in the fad.

“I like my scrunchies too much,” she said.