That's a good point about the dull blade. I saw a Korean video of this sort of scraping massage being done with a small flat rounded paddle type thing. It seems from the videos I've seen that both men and women have their entire faces done at the barbershops in Japan they want to chop all hairs everywhere.

What would be the best method for dulling a blade on purpose but have it be smooth? I don't have any straights to spare (my first is coming in the mail YAY!) I have SE and DE blades I could sacrifice. My guess is that an SE blade would be easier to fiddle with, I would feel more comfortable not shaving the hair on my face, it's not bothering anyone at the moment so probably best to leave it be.