Sahih Muslim 614
صحيح مسلم#614SahihAbu Qatada reported it from his father that the Messenger of Allah (ﷺ) said:When anyone amongst you enters the privy he should not touch his penis with his right hand
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 2:81