Professor Yaffle
Butterbeans and Breadcrumbs
And the particular example, if anyone who's not black is honest about it, is something that probably everyone wondered about at one time. When the first major 'fros were out in the 60s, most people who were not black or intimate with blacks had no idea whether it felt like a big fluffy pillow or a wire scrub brush or something in between. I remember when the "wet look" came back in whatever decade that was and a white guy asking another white guy if he could feel his "Poindexter". It's just curiosity coupled with minor boorishness.
As I said, the best example is guys who shave their heads. Anyone who's gone that route knows that people of all sizes and shapes and colors and genders will ask if they can rub it.
Its also similar to the phenomenon that most pregnant women experience, where people want to touch their belly.