Here is a funny editorial from a November 1906 Popular Mechanics magazine. Apparently, even back then people didn’t know why they licked their pencil points. You still see it once in a while now, but it must have been much more common 104 years ago. The author claims that nearly everyone other than “newspaper men and stenographers” wet their pencils. “It hardens the lead and ruins the pencil,” he laments. He tells the story of a pencil-loving newspaper clerk who was tired of customers licking the pencils they borrowed from him, and the story concludes, “Surely no one who reads this will ever again wet a lead pencil.”
(The article is next to news that a US company had just sold Russia the largest-ever gasoline engine for a submarine and an ad for a DIY wireless telegraph that “will work up to a mile.”)
I read somewhere that pencil licking was to activate the dye in copy/indelible pencils. So I licked a vintage red Dixon Anadel and asked my wife if my tongue was red. Her horror that I’d lick a pencil was only matched by the big red splotch on my tongue! Don’t ask me what it tasted like; I hastened to some strong coffee.