What is that accessory featured around Japanese gods' necks? It's like a...fluffy...thingy. It floats around their head and past their shoulders and down to their waist. I see it a lot. The two characters with it who come to mind are Guren from Shounen Onmyouji and Elsie from The World God Only Knows, but there are others with the same accessory. I'm just curious as to what it is. Attached is Guren with the...thingy.
This is actually a culture/belief thing, so it is a real thing. 
It occurs in many Asian countries, like China and Japan.
Here is a picture of it in real life:



Basically, it is a silk scarf, a really long one. It is not only used by gods; in the ancient times, dancers and women performing in front of people with some sort of power (such as money or governing) would usually wear this.
When people in real life wear it, it obviously won't be like that; it would be like a normal scarf, as you can see from this picture:



In there the scarf is floating around the woman: this is to bring out her aura and beauty.

That's the basic idea, though I might have missed certain details. If anyone is reading this and think I didn't put down the correct answer, please add on. Hope this helps.