(very) Retro AltBoobWorld : The Countess of Somerset. But is she actually wearing an open-fronted dress? The shape suggests she is, though she also has shoulder-boobs. Perhaps it's the corset.
Rules (fashion styles) of AltBoobWorld. See comments for brief list, but basically please don't be posing in underwear or lingerie, please don't be fully topless (must be clothing + boobs) and please don't clumsily roll up your top or pull it aside.
