Allah's Messenger (ﷺ) said, "Whenever anyone of you drinks water, he should not breathe in the drinking utensil, and whenever anyone of you goes to a lavatory, he should neither touch his penis nor clean his private parts with his right hand."
Sahih al-Bukhari Book 4, Hadith 19
← Previous Hadith Whenever Allah's Messenger (ﷺ) went to answer the call of nature, I along with another boy used to carry a tumbler full of water (for cleaning the private parts) and a short spear (or stick).

Sahih al-Bukhari Book 4, Hadith 18 Next Hadith → The Prophet (ﷺ) said, "Whenever anyone of you makes water he should not hold his penis or clean his private parts with his right hand. (And while drinking) one should not breathe in the drinking utensil ."

Sahih al-Bukhari Book 4, Hadith 20