The act of: removing ones clothes and turning on the shower, then the requirement of a poo occurs. A tamed impala then happens when the poo is not flushed so as to not affect the shower's temperature. It is then forgotten and left unflushed for the next bathroom user to find. The second user must find the unflushed act for it to become a tamed impala
Turning on the shower stripping off and then doing a poo naked and leaving it unflushed so the shower temperature is not affected. The opposite is rarely known unless the producer of the "untamed impala" informs the second user that they flushed their poo and got burnt in the shower.