A felt-tip pen gliding over a snow white piece of paper. The rapping of fingernails on a leather-bound book. Whispering.

Autonomous Sensory Meridian Response (ASMR), also known as a “brain orgasm,” has much uncertainty swirling around it in the scientific community. But for a tightly-knit following, ASMR is felt as viscerally as a biting wind or a scalding stove. Often described as a fuzzy tingling sensation, ASMR registers in the head and works its way down. Despite its nickname, most people describe it as less of a sexual high, and more of a deeper, euphoric wave that washes over them. The sounds and visual sensations elicit feelings of comfort and security. And for champions of ASMR, it’s just about the greatest feeling there is.

ASMR isn’t confined to sounds. A whole branch of ASMR research, spearheaded by the woman who coined the term, Jennifer Allen, deals with the pleasurable experiences people have in their daily lives. For some, it’s getting a haircut. For others, it’s watching someone fold towels. Some enjoy watching other people assembling Lego replicas of famous skyscrapers. Others prefer watching infomercials. Whatever your preference, the backbone of ASMR lies in the compulsion for gentle, rhythmic motions. They aren’t jarring, and they aren’t sharp. They’re tranquil. And they’re soothing.

“I was first aware of this sensation when I was a child; my history teacher had a very specific way of speaking,” writer Nicholas Tufnell explained in his account of ASMR for The Huffington Post. “Her consonants were pronounced with a unique click, her plosives were soft and gentle and her voice was both slow and considered. I would often zone out. I've never been much good at history as a result, but I've figured as long as I know the important things like Henry VIII had 10 wives and WWII ended in 1985, it doesn't much matter.”

Clinical research into ASMR has been spotty thus far. The ASMR Research Institute, founded by Allen, explores the brain’s inner-workings hoping to answer all of science’s questions. Why, for instance, would humans need to care, evolutionarily speaking, about getting their hair cut or listening to a history teacher lecture on Henry VIII?

The answer, according to ASMR Research Institute team leader, Karissa Ann Burgess, is that ASMR may serve as a byproduct of the bonding rituals performed by nonhuman primates. Apes and monkeys are often found grooming one another in much the same way humans respond to a tug of the hair at the base of their spine or a set of well-placed fingers running through their scalp.

“Dopamine could be involved, serotonin — the feel-good hormones,” Burgess told Time. “There’s also some interesting theories that it might be a sort of bonding phenomenon and triggers the release of oxytocin, which is the bonding hormone.”

Neuroscientist Dr. Steven Novella theorizes that this release of pleasure and bonding hormones, which occurs in every vertebrate mammal and is hardwired into the behavioral feedback system, still varies at more detailed levels. This could explain why some people experience more typical ASMR from light scratching on their skin, while others enjoy more unusual sensations.

“We have a range of likes and dislikes,” Novella wrote earlier this year on his blog, The Ness, “and there are individuals and even subcultures that seem to have a different pattern of pleasure stimulation than what is typical. (Perhaps in some cases this is largely cultural, not neurotypical.) S&M comes to mind. If reports are accurate, there are some people who experience pain as pleasurable and erotic.”

In this, ASMR may be more of a learned association than one that is hardwired. Consider the sprawl of phobias, many of which people don’t begin to suffer from until they’ve learned about the fear.

“What we need at this point are functional MRI and transcranial magnetic stimulation studies that look at what is happening in the brains of people while experiencing ASMR, versus typical controls,” Novella concluded. “Are their brains really different, and in what way? I also wonder if the same or similar experience can be artificially induced in typical (non-ASMR) people.

“This is just another example of how our brains are fantastically complex and weird,” he continued. “How else can you explain the existence of videos of whispering Latin and wrapping paper noise on YouTube?”