I see like an outline of barely visible light. It is sort of watery like you said.
I see them, too.
It's a combination of things. It's mostly just eye jitter combined with the pinhole camera effect of light focusing and after imaging that your eye perceives. Essentially a trick of the light and environmental conditions (humidity, backlight/lighting conditions, etc) as well several oddities in the way that the eye functions.
You can make a pinhole with your hand (this is how Bukowski masturbates)
and look through it to see how looking past edges of objects helps your eye focus by cutting down on scattered light from the object that you're viewing that the object you're looking past is cutting out. If you experiment with the edge of your finger and distant objects with high contrast or especially backlit objects (more on this later), you will perceived the edges of objects bending around your the edges of your finger. This isn't light bending, but scattered light that the lens of your eye didn't quite catch/focus properly that the back of your eye isn't getting anymore.
I'm not going to explain afterimage between two high contrast objects - I assume everyone is familiar with them.
Your eye is constantly moving around and jittering, even when it is looking at a single, stationary object. Normally, this eye jitter is not consciously perceivable. Here is a demonstration to detect gross eye jitter (your eye actually has more high frequency microjitters as well, but it's not perceivable in this demo):
Your eyes are constantly moving around and are constantly receiving slightly different sets of images. Look at of your computer screen, then slightly nod and shake your head at the same time. Notice that along the edges of the screen, there is new info popping in and out behind it. Your eye jitter is doing that on it's own, only on a much smaller scale. Eye jitter is actually a good thing and improves perception, but between the constantly shifting images and the afterimages, the "aura" around objects in certain lighting conditions is one of the side effects.
I was going to get into lighting conditions as well how humans arrange objects (such as furniture and taller, sightline obstructing objects tending to be along walls and while humans tend to be away from and backlit by walls) and how and why the human tendency to focus on other humans makes this aura stuff more perceptible in other humans but this post is getting too long. Basically, if you stared at a dark colored La Z Boy in a very light colored room, you'd notice a "aura" around it, too.
Also, here's a simple question - if humans actually had a living aura and certain people could perceive it, then why can't you see that shit in the dark?