I once had a flatmate called Tom, who behaved very oddly when our cleaner came round. On mornings when she was due he’d become strangely excited, like a man waiting for a date, though Madge (70) seemed an unlikely target. I would leave the flat so that Madge could get on with it, but Tom would insist on staying. He’d settle himself into an armchair, close his eyes and sit there, still as a toad, as she hoovered and dusted around him. Eventually I asked him about it, and he confessed. Listening to Madge, he said, ‘makes my brain feel nice’. As he explained it, the sounds of cleaning, sweeping and busying about sent delicious shivers running across his scalp. ‘It’s blissful — like a tingling feeling. But it’s not at all sexy,’ he was keen to stress.

I said: ‘Don’t fret, Tom. That all sounds… normal.’ I had no idea then just how very normal Tom was.

This was in 2007 and, as it happens, that very year a group of people gathered in an online chatroom to discuss that very feeling. They didn’t all depend on cleaning noises: the sounds that set it off were many and varied. For some it was a whispering voice, for others a tapping sound or the crinkling of paper, though everyone agreed that a feeling of being given personal attention and cared for helped. One of the chatters concocted a plausible-sounding bit of jargon: autonomous sensory meridian response, ASMR for short, and that was what stuck. And that’s what has, more than a decade later, become an internet phenomenon.

Any discussion of what exactly ASMR is usually comes to the same conclusion: that it evolved as a response to primate grooming. Chimps and gorillas, it’s said, fall into the sort of ecstatic state Tom describes when they nit-pick and pair-bond, and some humans, like Tom, retain the ability. I like to imagine the Toms of the past: the groups of shifty hominids who sat a little apart, listening to the drip of ice-age melt-water; the Victorians who hurried home when the chimney sweep was due. I like to think back to when ASMR was a private affair. Because it sure isn’t now. Once it had a name it became searchable, and once it became searchable it became monetisable, and now all manner of people make a living making videos that trigger ASMR — ASMRtists they call themselves. If you get it just right, if the timbre of your whisper does it for the ASMR gang, you can make a very decent living. You’re effectively a dealer, but the stuff you sell is legal, and there’s no need for a supplier because your customers make the drugs themselves.

Most ASMRtists are themselves members of what they sometimes call the ‘tingle tribe’. WhispersRed, for instance, is a nice-looking British girl, real name Emma Smith, who videos herself speaking in a quiet, breathy voice — slowly and dreamily, but with great focus like a very attentive nurse, or a psychopath. To me, WhispersRed sounds as relaxing as Hannibal Lecter. But when I played a video to Tom, that familiar blissed-out smile crept over his face.

American teens, the beadiest of entrepreneurial groups, cottoned on early to the profit potential. Is it wrong for children to make videos for adults to get off on? It’s such a recent phenomenon that no one knows. One 13-year-old ASMRtist called Makenna from Colorado hit the big time last year with a video entitled ‘Eating raw honeycomb — EXTREMELY sticky mouth sounds’. More than 12 million have watched it, and Mak and her manager mom make $1,000 a day in advertising revenue. Eating sounds are extremely popular amongst the ASMR gang. And if, like me, you don’t get tingles from the videos, they’re likely to be among the most disgusting things you’ve ever seen. One Canadian girl, ASMR SAS, eats to order for cash. I might never forget the clip of her dipping king prawns in melted cheese and eating them right up against the camera lens. It was the squelching, crunching sound — and who dips prawns in cheese?

Of course there’s something touching about all those lonely tinglers finally getting together. But there’s also something troubling about ASMR, especially the rate at which it’s spreading across the web.

More and more companies are making adverts designed to activate ASMR. If you can give some of your audience an actual high, why wouldn’t you? In this year’s Super Bowl, there was an ASMR commercial for Michelob Ultra Pure Gold beer. Model Zoë Kravitz (daughter of Lenny) whispered and tapped on the bottle like a pro. Ikea, Taco Bell and KFC have all done ASMR ads. Google’s brand-consulting service recommends it: ‘We are not just talking about an enormous engaged audience to tap; we are talking about an enormous engaged audience that is already using your brand,’ it writes. ‘ASMR-tists often employ objects, especially food products, to create the tingly effect: crinkling wrappers, chewing candy, cracking open cans.’ ASMR and junk food are a perfect fit, says KFC’s marketing boss. ‘There’s a lot of comfort associated with ASMR, and that’s what our food delivers.’ How much comfort do 21st-century adults need?

But my worry is that it’s not going to end with adverts. What if they start doing train times in ASMR-speak to keep the commuters calm; what if the robot tills in Sainsbury’s become oddly loving and sibilant? Imagine the Chancellor licking his lips and gently tapping the mic as he reads out the budget. With dread, but somehow unable to stop myself, I typed the words ASMR and Brexit into Google. Sure enough…

On the BBC’s website is ‘Brexit ASMR: whispering the withdrawal agreement’: ‘Simply put on your headphones and take in this ASMR Brexit experience from our Brussels reporter, Adam Fleming.’