@IvanaJackow: Basically an off-screen dom has put these two sisters into a cage and is taunting them while teasing them with a vibrator and making them wear rubber and kigurumi masks while gradually turning up the heat in the room. No big complicated story, most of the dialog is just moaning and heavy breathing.
Since nobody else bothered to do so, the artist is purinpu(ぷりんぷ): http://www.pixiv.net/member_illust.php?id=11246147 And sauce for this set is: http://www.pixiv.net/member_illust.php?mode=medium&illust_id=47546994