why I do it .. its because when I drag the print of the pad of my thumb across my blade edge , it catches slightly at the print of my thumb if its sharp .. it gives me feedback on how sharp sharp is , a slight grab , a keen grab, a seriously keen grab at the ridges of my thumb print ... something I personally dont get from testing it on my nail . Im not happy with "sharp" or " not sharp" I have sharp enough for kitchen , sharp enough for clean slaughter work, sharp enough for skinning a sheep with a full fleece thats been in a sandstorm , and stupidly crazy scary sharp for my personal pocket knife just cos I like to show off what sharp can be at times , among other grades of sharp . I can tell what Im dealing with by dragging my thumbprint seriously lightly across ( not along , but across ) a blade edge . This is why I do it how I do it .
Ive been doing it this way since I was about 6 yr old .. close on 40 years now , I dont recall having bled from it yet . Not saying i wont , there is always a first time .