Heterosexual sex popular in Africa. Dust or powder is used to dry the vagina and
increase friction. It also causes breaks the skin of both parties increasing the
transmission of diseases. If women are well-lubricated the presumption is that they
are promiscuous and the lubrication is semen from other partners. Men are thus
squeamish about wet vaginas. I would imagine it would be painful for the male as
well, so I doubt the motive is personal pleasure.