When sex is a topic that most of us feel more than a little hot and sweaty talking honestly about - and not in a good way - knowing what is normal can be as mysterious as knowing what all those weird toys in Ann Summers actually do.

But when what turns a person on takes over their life and an otherwise quirky fetish becomes debilitating, this is known as paraphilic disorder.

To make matters worse, sex remains a little-researched and little-understood topic. Among those trying to get to grips with sex is Debra Soh, a researcher and PhD candidate in sexual neuroscience at York University in Toronto, Canada. She has used brain imaging techniques to better understand hypersexuality and paraphilia in men.

Separate research published in 2016 found that what are perceived as sexual anomalies are more common than previously believed.

The study assessed 1,040 residents of Quebec on their experiences of sexual behaviour that are considered abnormal in the widely-used The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5).

It revealed that 35 per cent of people were interested in voyeurism, 26 per cent in fetishism, and almost a quarter in frotteurism - or rubbing’s one’s genitals against someone without their consent - and just under a fifth in masochism. These proclivities were almost as popular among women as they were in men.

So, what is the difference between a kink a paraphilia, and paraphilic disorder?

“A paraphilia is defined as an atypical sexual interest,” explains Soh.

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“It is a person's primary sexual interest and the most up-to-date research suggests paraphilias are immutable, meaning they are with a person from very early on in life and they can't be changed.”

“Some of the most common forms include voyeurism, exhibitionism, and fetishism, which is a preference for inanimate objects or particular parts of the body.”

However, urophilia, or sexual interest in urine, is also surprisingly common, according to Soh’s research interviews.

“Other lesser known paraphilias include vorarephilia, which is the sexual fantasy of being swallowed alive by another living being, and diaperism, or the interest in being cared for like an adult baby.”

Still, these unusual sexual preferences aren’t actually medical issues.

“A paraphilia becomes a paraphilic disorder if it causes the individual impairment in their day-to-day functioning, or causes harm to themselves or their partners. In this case, I do think treatment is warranted," says Soh.

In those instances, research shows paraphilias can't be changed, but it can be managed with sex-drive reducing medication and therapy.

“There are, however, plenty of people who have paraphilias that aren't hurting themselves or other people, so there is no reason for them to be pathologised," she stresses.

But, that doesn’t make it any easier to confront a partner about a more left-field preference, from a foot fetish to sploshing: where people enjoy watching others sit in food.

"Sex is still a rather taboo topic in our society, and even talking about vanilla or ‘normative; sexual behaviours is stigmatised," says Soh. "It's very common for someone who experiences a paraphilia, or multiple paraphilias, to feel a great deal of shame around these interests, even if they are consensual."

“My best advice to your readers would be, if you are kinky, to find yourself a partner who is similarly kinky or open to kinkiness. I've seen many, many relationships and marriages end because a monogamous couple was not compatible in this regard.”