Last night I was honing a vintage Puma wedge, and I didn't feel like getting up and finding one of my wife's hairs, so I decided to try the thumb pad test for the first time ever.

This was after the 4000 stage of honing.

I wet my thumb and very lightly pressed my thumbpad on the edge. And when I say pressed lightly I mean just enough to actualyl feel that I touch something.

Creepy.
I cannot really describe the feeling because it is unlike anything I ever felt.
When I touched the edge I felt it going through the ridges that make up the fingerprint. The place where my TP touched the edge felt very hot, like I was touching a hot plate, except there was also a feeling of electricity to it.

I suspect this has something to do with the nerve endings getting stimulated by the metal.

Anyway this is a useful test. Combined with the flow of water over the edge, it tells me everything I need to know.
But it is also a bit scary.