رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 758
The Book About the Etiquette of Eating
Etiquette of Drinking Water
وَعَنْ أبى قَتَادَةَ رضى اللَّه عَنْهُ أَنَّ اَلنَّبِيَّ صَلَّى اللَّه عَلَيْهِ وَسَلَّمَ نَهَى أَنْ يَتَنَفَّسَ فِي الإِنَاءِ.((مُتَّفَقٌ عَلَيْهِ))
Abu Qatadah (May Allah be pleased with him) reported: The Prophet (ﷺ) forbade breathing into the vessel while drinking. [Al-Bukhari and Muslim].
Riyad as-Salihin, 758