At work we have these hardwood chairs that have a black, satin finish. The first time I sat in one, I was somewhat surprised to find a spot in the middle of the chair upon standing. I assumed I must have sat in something, but couldn’t find anything on the seat of my pants.
The next time I used this chair I carefully inspected the surfaces prior to sitting down. When I got up, I noticed a similar spot. It was a golfball-sized, circular spot where the chair had fogged up (I have to sit still for a few minutes in order for the spot to form). It seems to form directly beneath the region in between my testes and my anus (aka the “choad”). The fog disappears after a few minutes and leaves no residue, so it appears to be some sort of water vapor. Furthermore, this fogging occurs regardless of whether or not I fart.
Is the room cool? I’d suspect it’s just vapor/heat from your body condensation on the chair.
Next time your in that room, I’d guess that if you place your a cupped hand on the chair for a similar length of time you’ll get the same results.
I suspect it is simply that the perineal area is restricted from ventilation when sitting on a hard surface and that body temps are causing a blush in the finish.
This can be seen, for example, when the forearms rest on a finished table.