Move over, sleepovers. Here's why some families are hosting 'sleepunders' instead.

Sleepovers are a big deal for kids — for some, it's the first time sleeping away from home. It's also an excellent excuse to stay up past their usual bedtime and hang out with friends. But sleepovers can also come with anxiety, and some children get so nervous at a certain point in the evening that their parents need to be called to come pick them up. Enter the sleepunder.

Sleepunders allow kids to get many of the perks of sleepovers without the actual sleeping over part. Basically, they can have a lot of fun and still go home to the familiar setting of their home.

Fertility coach and mom Becky Ackerman tells Yahoo Life that she did a sleepover with her 8-year-old daughter and three friends in March. "We chose this route because she likes the idea of a sleepover but she's not much of a night owl," Ackerman says. "This option gave her the best parts of a traditional sleepover without the possibility of a meltdown of any sort."

Ackerman says her daughter's friends arrived at 4 p.m. in their pajamas and pillows, played a bunch of games, ate pizza and had cupcakes. From there, they watched a movie. "When the movie was over at roughly 9:30, we drove everyone back home," she says. "It was a total blast, and so cute! Everyone was pretty tired when they got home, and I don't think any of them really wished they'd been able to spend the night."

Ackerman says the event was "really easy to host," adding, "we didn't have to think about where everyone would sleep, we didn't have to deal with noise after the rest of us went to bed and we didn't have to deal with breakfast."

Ackerman's family isn't the only one who has done a sleepunder. Fashion influencer and children's book author Eva Chen recently mentioned in her Instagram Stories that her children, who are age 8 and under, had one. Parenting expert Karen Aronian tells Yahoo Life that her high school daughter and middle school-aged son prefer them. "They know that a night without a wink does not make for a good next day," she tells Yahoo Life. "They're also at an age where they recognize what works for them. They still go to sleepaway camp and will do a campsite sleep-out as a group activity [but[ they realize that they prefer their bed."

But how does a sleepunder work, exactly? And is it OK to leave a regular sleepover early? Experts weigh in.

How does a sleepunder work?

There are no set rules for sleepunders, so parents and kids can tailor this to suit their needs.

"Sleepunders are a wonderful compromise for families that have decided to opt out of sleepovers for any number of reasons and present an opportunity to include children that are not yet ready for full sleepovers," psychologist Schenike Massie-Lambert, clinical coordinator at the Children's Center for Resilience & Trauma Recovery at Rutgers Health - University Behavioral Health Care, tells Yahoo Life.

Sleepunders usually include the standard trappings of a sleepover — food, popcorn, games and a movie, Dr. Danelle Fisher, a pediatrician and chair of pediatrics at Providence Saint John’s Health Center in Santa Monica, Calif., tells Yahoo Life. It's just that everyone goes home at a designated time.

What is the benefit of sleepunders?

Sleep and a lowered risk of anxiety are the biggies, according to doctors. "With sleepovers, the kids traditionally get so excited that they may not sleep well," Fisher says. "A sleepunder gives kids a little sense of empowerment that they can have social time but don't have to interrupt their sleep to do it."

Lynelle Schneeberg, director of the Behavioral Sleep Medicine Program at the Connecticut Children’s Sleep Center, tells Yahoo Life that kids may have a "sleep crutch," which is often their parents. "When it's time for a sleepover, some kids know that they might not be able to fall asleep because their sleep crutch isn't going to be there," she says. "The sleepunder concept allows kids to get together and then go home to their bed, where their usual ways to fall asleep are available."

Anxiety can be a big factor in sleepovers for kids too, Fisher says. "Some kids don't always feel comfortable with a sleepover," she says. "We should always elicit what the kid's desire is."

Sleepunders can even help ease the minds of parents who are concerned about potential safety issues with their child sleeping over at a house when they're not there, Massie-Lambert says.

Is it OK to accept a sleepover invite and then leave early?

Sleepovers aren't always one-on-one and some kids may be ready to spend the night, while others aren't. Doctors say it's OK to leave a sleepover early if parents don't feel their child is ready for it. "It's just important to discuss it ahead of time so that both sets of caretakers understand the situation and that there are no bad feelings," Fisher says. "If your child says they want a sleepover but really need a sleepunder, you don't want them to have negative associations with it." (It's just important to communicate to the child in advance that they'll be leaving the party "early," Fisher says.)

Schneeberg recommends stressing to a child that they're "there for all the fun and really just missing out on the sleep part."

When are kids generally ready for sleepovers?

"It's really kid-dependent," Fisher says. Some kids — usually those with older siblings — may be ready for a sleepover at a familiar home, like their grandparent's house, as young as 4, she says. "Some are not ready until 10, 11 or 12," Fisher says.

In addition to asking a child if they feel ready for a sleepover, Schneeberg suggests looking at how well the child can put themselves to sleep. If they need a parent or a sibling there to fall asleep, she says they're not ready.

Fisher stresses that a child's readiness to have a sleepover doesn't say anything about their development. "It doesn't mean anything in the big picture," she says.

If a parent decide that their child isn't quite ready for a sleepover, experts say they can go the sleepunder route — or even host one themselves. "I would for sure host a sleepunder again," Ackerman says.

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