With Christmas just 26 days away now, many Britons will be excitedly dusting off their best Christmas jumpers. 

For most people, these festive garments are novelty items that end up stuffed back in the attic when January rolls back around. 

However, others are so obsessed with their jumpers that they actually derive sexual pleasure and arousal from wearing them. 

That's according to Dr Mark Griffiths, an expert in Behavioural Addiction at Nottingham Trent University, who has detailed the strange 'wool fetish' in his new book, Sexual Perversions and Paraphilias. 

'Human beings appear to have the capacity to fetishize about almost anything,' he explains in the book. 

'Woolies are individuals who derive sexual pleasure and arousal from wearing wool, typically in the form of full-body "wool suits".

Dr Griffiths believes that this may be a relatively new fetish. 

'Given that there is absolutely no scientific research on woolies suggests either that the fetish does not really exist or that it is a relatively newly realized fetish,' he added. 

'Woolies' are people who get sexual pleasure or arousal from the feeling of soft wool on their own, or others' skin. 

According to the experts, wool fetishes sit on a spectrum ranging from fairly tame to extreme.

For example, some users simply enjoy the subtleness of a woman wearing a turtleneck sweater. 

However, at the other end of the scale, some woolies enjoy being 'partially mummified' in layers of blankets. 

Back in 2014, Dr Griffiths was asked to comment on several cases of 'woolies' for a TV documentary on the Discovery Channel, called Forbidden. 

'One of the woolies featured was an American, Scott from Florida, who perhaps unsurprisingly ran a small company selling sweaters and said he had a "lifelong obsession" with wool,' Dr Griffiths explains in his book. 

'As a boy he claimed he would steal sweaters to hide in his school locker or in the woods near his house. 

'At the time of recording, he had a collection of about 3,000 sweaters and claimed to be sexually attracted to anyone wearing a sweater including men (even though he is heterosexual).'

Scott described his love for wool as a 'secret fetish', because no-one knew that he was actually getting aroused by walking the streets in his jumper. 

The documenatry also featured a German women called 'Lady Mohair', who sold full-body knitted outfits to people worldwide.  

'In the programme she introduced the audience to a few of her more "eccentric" woolies such as "Knuti" who assumed the persona of a woolly polar bear,' Dr Griffiths recalls in his book. 

While there is yet to be any scientific research on wool fetishes, Dr Griffiths says that he's convinced they're legitimate.  

'My own view is that wool fetishists do exist,' he added. 

'But, as with many other niche fetishes I have covered, the incidence and prevalence is likely to be very small.'

You can find out more about paraphilias in Professor Griffiths' new book, Sexual Perversions and Paraphilias: An A-Z.