(18) باب النَّهْىِ عَنْ الاِسْتِنْجَاءِ، بِالْيَمِينِ
Abu 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.
Reference: Sahih Muslim 267b
In-book reference: Book 2, Hadith 81
USC-MSA web (English) reference(deprecated numbering scheme): Book 2, Hadith 512