Four girls from a rather questionable visual novel that I stumbled upon long ago. They spend most of their time naked and just enjoying getting laid as a sort of extreme beach vacation. We don't really know their names even, just the nicknames they go by.
Matsui: BinBi, Matsui, blonde hair, long hair, yellow eyes, huge breasts
Nakau: BinBi, Nakau, grey hair, short hair, yellow eyes, small breasts
Sukkya: BinBi, Sukkya, brown hair, short hair, green eyes, large breasts, dark-skinned female
Yoshinon: BinBi, Yoshinon, black hair, long hair, ponytail, blue eyes, large breasts