Well, the little rodents like that! Courageously and in a good mood, they romp around in and out of their mini sand bath. In order to maintain their fur as neatly as a chinchilla should, they wallow themselves in the sand and thus meet a natural need of the rodent.
Only when a slightly older chinchilla comes along and also wants to share in the bathing pleasure does a small problem arise: the mini bath is much too small for him. Did he forget that there is also a larger sand bath available for him? In the second, also very cute, video you can see what the sandy bathing fun looks like with adult chinchillas.