The actual 'bleaching' of the skin around the anus, for those with light colored skin.
Purely for cosmetic purposes, a cream containing an active ingredient, hydroquinone, is used to 'bleach' the skin around the anus.
The concentration is about 20%.
There is no practical purpose for such 'bleaching'.
Noteworthy: Banned in many countries, the active ingredient is considered to be carcinogen.