“IMAGE: Acoustic tribology diagram via NIZO. First, drink some black coffee. Next, rub your tongue against the roof of your mouth. It should feel a little rough, like very fine sandpaper: the tiny bumps on your tongue, called papillae, are raised just enough to create friction against your palate.”

Read More: http://www.ediblegeography.com/listening-to-what-the-tongue-feels/