In various parts of the world people like to bleach their bits. Penises are being lightened in Thailand, in America lightening has been suggested for the vagina and anus. It's a delicate subject because it balances the right to do what you want with your body, and equating good appearance with being pale.
Professionals who perform the procedure say that are serving people with "discoloration", but perception of a problem in that regard is subjective. Darker skin in all of these areas is anatomically normal and might be more accurately called simply "coloration". The perception that the body should have a uniform color seems to have come from porn stars modifying their orifices to get this effect.
All of the substances that reduce pigment are uncomfortable and most are suspected or known carcinogens. Peer-reviewed research on the reasons for intimate bleaching, and the effects on health, are completely absent as far as I can tell. Businesses continue to provide these services in the absence of evidence based guides about their ethics of when to provide them or medically safe protocol.