Sunan an Nasai
41
Sahih+2

It was narrated that Salman said, that a man said to him:"Your companion (meaning, the Prophet(ﷺ)) even teaches you how to go to the toilet!" He said: "Yes, he forbade us from facing the Qiblah when defecating or urinating, or cleaning ourselves with out right hands, or to use less than three stones

SahihAbu Ghuddah
SahihAl-Albani