There was less on Wikipedia than I thought there'd be, such as an explanation. The only ones were that it makes the vagina feel tighter, which is not true, not in any good way, and that some people just like it, which isn't an explanation.

I'm also thinking that if it were remotely pleasurable, this wouldn't be unique to shithole Africa, cuz people have figured out every good way to fuck and a lot that are specific. The heirs of the Greeks have never heard of "dry sex".