The mild-mannered man looks calmly into the lens, a Japanese-style painting of a tree bough with red blossoms lit by a full moon on the wall behind him. He's going to gently brush my ears now, he says. He moves closer, now out of frame apart from one ruffled white sleeve of his dress shirt as if he's cupping the side of my head, and a soft, repetitive rustling sound comes through my computer speaker in right-hand stereo. "Aaaaaaaah," he breathes intimately. "You're doing a very good job. You're completely safe. You're very relaxed."

He says he's going to get an item. The screen of the YouTube video fades briefly to black before he returns. "Thank you for waiting," he says politely. "We'll just moove" - he draws the word out slightly, articulating carefully - "into the next part of our session."

Autonomous Sensory Meridian Response is often called 'brain orgasms'.

The 39-year-old Australian from the Gold Coast, known as "Dr Dmitri"*, is a worldwide star of a phenomenon called ASMR, or Autonomous Sensory Meridian Response, that thanks to YouTube has become a rapidly growing subculture. It's triggered by activities including whispering, tapping, crinkling, meticulous processes and personal attention and can last up to 20 minutes.

The videos on Dmitri's ASMRMassage channel which can trigger the experience get 2 million hits a month, with 16 million in total. He's the most popular man in the world making such videos, outranked by five women.