The commentary should explain enough, but in case you don't know the whole backstories of these maids: they're 'night and day service' kind of maids, so basically trophy maids (maids that are kept for their beauty to impress visitors in early to mid-victorian era) taken to the lewd extreme. Their owner was hosting a ball but they got the wrong dresscode, it was formal kind of party and not the debauched kind.
