Webmasters notes:

When I first read this one I had to chuckle to myself. I had never heard of it before and I can't wait to get someone with this. I may try something other than pinching because the friction may cause them to feel the grit on my fingers.  For example, instead of pinching I may just touch them with my ashy index finger right in the middle of the forehead or the tip of the nose.

You get everyone in on the trick but the victim. (When he gets up to use the restroom would be a great time to let everyone in on it.)   Have a glass in front of you and an ashtray so you can dip you finger in it and then in the ashtray. Tell the victim they have to pinch in the same place on the next person as you pinched him at (ex. I pinch him on the cheek he has to do the same to the next person, I pinch on the chin he does too) if he messes up he has to take a drink. (I gather that we're supposed to tell the victim it's a drinking game.) While he is pinching the next person you dip your finger in the drink and in the ashtray so you get ashes on his face the next go round by the 8th or 9th time his face is all full of ashes.