Only men and real women are allowed to walk around the house and touch the floor. With her flat chest, there is only one appropriate place for her: the toilet. Sitting, however, would be too comfortable for her. Therefore, her master decided to give her a choice: stand on the toilet or sleep in front of the house.
In winter, sleeping in front of the house is hardly an option, so she has no choice other than to stand on the toilet. Over the years, she had to learn to sleep while standing without falling down – and in those few cases where she still falls down after falling asleep, her master’s tit whipping is much more painful than the pain from falling.
At least she has finally found a reason to be grateful for her flat chest: if she actually had real tits, if would be much more difficult for her to sleep while standing because the weight of her tits would make keeping the balance much more difficult.