Why do people lick/wet the tips of their pens/pencils?

I was wondering where the idea of wetting ones pen or pencil originated?

I’ve found that if a pen is sitting upcapped for a while, the little dot of ink at the tip can dry out, so a tap on the tongue gets things rolling again.

Pencils- no idea.

A Google cache at the Stumpers site offers these possibilities:

Long time fountain pen user here.
Fountain pens’ ink at the writing tip would dry out, preventing ink flow. Wetting the tip got the ink flowing again. No cite.

Because it tastes so good?