They’re soaking up some rays where the sun don’t shine.

The hottest trend gripping wellness die-hards is tanning their cans, or “perineum sunning,” as influencers are calling it.

“In a mere 30 seconds of sunlight on your butthole, you will receive more energy from this electric node than you would in an entire day being outside with your clothes on,” says an influencer, who goes by Ra of Earth. In a viral video that has racked up more than 35,000 views, he gestures toward the sun as three naked men lie down, point their backsides to the sky and make sounds of pleasure.

Ra of Earth has also posted a step-by-step “Sun Worship exercise” pulled from “The Tao of Sexology: The Book of Infinite Wisdom” by Dr. Stephen T. Chang that says the practice can help keep the area “healthy and free of germs.”

Chang and Ra of Earth aren’t the only ones, either. Other influencers appear to be just as inspired to catch some ultra-vile rays.

“[Thirty] seconds of direct sunlight injection to the anal orifice is equivalent to being outside in the sun all day!” writes influencer Troy Casey.

One Californian claims butt-chugging vitamin D not only helps her sleep better but helps to regulate her hormones.

“For the past few weeks I have included sunning my bum and yoni into my daily rising routine,” a woman who goes by Metaphysical Meagan captions an image of herself fully naked on a rock. Meagan says she first learned about perineum sunning through her study of Taoism and has recently given up her morning cup of coffee in favor of sunning her anus.

The phenomenon caught the wider internet’s attention after one Twitter user posted Meagan’s photo and caption, to the tune of more than 84,000 likes.

Even A-listers are sunning their bums. “Big Little Lies” actress Shailene Woodley, who is known for her holistic lifestyle that doesn’t even include a TV, has admitted she’s also practiced a version of perineum sunning.

“Another thing I like to do is give my vagina a little vitamin D,” she told Into The Gloss in 2014. “I was reading an article written by an herbalist I studied about yeast infections and other genital issues. She said there’s nothing better than vitamin D. If you’re feeling depleted, go in the sun for an hour and see how much energy you get. Or, if you live in a place that has heavy winters, when the sun finally comes out, spread your legs and get some sunshine.”

However, medical professionals are far from convinced the practice has any merit.

“There is no evidence that sunbathing in this way has any effect on physical well-being,” Dr. Diana Gall of UK-based online doctor service Doctor 4 U tells Insider.

“Yes, practicing mindfulness and meditation, and getting your dose of vitamin D, is beneficial for mental and physical health, but you don’t need to damage your skin in the process from sun exposure,” she says.

Gall suggests that there are different and “safer” ways to practice mindfulness and adds that “there are no extra benefits of doing this naked in the sun.”

While influencers are currently letting sun shine in their back door, the Federal Trade Commission is having little luck convincing them to shed more light on product endorsements.