Aghori sadhus perform a bath not with water but with ash from a cremation ground. The hidden aspect is twofold: first, the ash is collected from a specific pyre (often a suicide or a child’s death) at midnight. Second, the bather recites a mantra that reverses the normal direction of prana . This bath is hidden because it violates the purity-pollution axis of mainstream Hinduism; it is performed in a state of ritual transgression, invisible to the pious.
The layout of an Indian bathroom isn't accidental. Many follow , an ancient architectural science. indian bath hidden