Everyone's walking around with bleached bum holes and we know who's to blame.

There’s a secret club you (I’m presuming) and I aren’t members of.

The anal bleaching club.

Entry into the exclusive, top secret society is simple – bleach your bum hair. (Please don’t.)

Unsurprisingly, you can’t tell at first glance who is and who isn’t – but the membership numbers are increasing significantly, apparently.

Which means you could be sitting next to a member AS WE SPEAK.

Demand for the beauty treatment-we-never-knew-we-should-or-could-even-do has grown by a quarter in 2017 alone.

"We have seen a rise of 23 per cent in the past year at the clinic. Laser therapy is the most popular, accounting for around 95 per cent and cream treatments about five per cent," Sheri Johnson, leading medical aesthetic clinic manager at HB Health of Knightsbridge told Glamour.

We discuss botox for your butthole on Mamamia Out Loud. Post continues below.

And we know exactly who's responsible.

Turns out their teeth aren't the only things those in the public eye are bleaching.

Experts say it's celebrities like Kourtney Kardashian along with reality TV stars and porn stars who are driving demand as it becomes more common in pop culture.

Kardashian admitted to having her anus bleached in an episode of Kourtney and Khloe take Miami, while Geordie Shore stars Sophie Kasaei and Marnie Simpson even helped each other do the treatment in one memorable episode. (Probably best not to watch while you're eating your dinner).

Fellow Geordie Shore personality Charlotte Crosby revealed she'd had it done during a celebrity dating show and it even became an iconic line from the film Bridesmaids, when Maya Rudolph's character says she had the treatment done and liked it.

The bigger question is why? Can our poor bum holes not be left alone? Are they not good enough as they are? WHO IS EVEN SEEING THE BUM HOLE OTHER THAN THE TOILET?

Anal bleaching is designed to lighten the hair and skin around the anus and is achieved by applying an acid to your "freshly waxed anus and rubbed in," according to Cosmopolitan. Doesn't that sound DELIGHTFUL?

You can get it done at a salon or even use an at-home treatment.

It's popularity occurred as a direct result of the rise of Brazilians, particularly as they were featured more and more in porn. With no hair to hide it, women reportedly noticed their, ahem, anuses were a different colour to the rest of their skin and wanted to change it.

As well as being, you know, totally unnecessary and another beauty treatment designed to make us feel like our bodies as they are not "right" as they are, experts warn anal bleaching can come with some nasty side effects.

New York City based dermatologist Doris Day told Cosmopolitan that if not done properly, problems can include strictures, "which make the opening smaller and bowel movements difficult, and tears in the anal canal."

"It’s not the most gratifying treatment. The darker pigmentation will always come back so it’s not permanent. And there’s also a chance of total depigmentation [ie, it would be totally white, rather than matching your skin color] or in some cases, because of how one’s skin reacts to the bleach, a darkening of the area."

You know what? We might, err, leave this one. Anus, you're off the hook.