رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 756
The Book About the Etiquette of Eating
Etiquette of Drinking Water
عَنْ أَنَسٍ رضى اللَّه عَنْهُ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّه عَلَيْهِ وَسَلَّمَ كَانَ يَتَنَفَّسُ فِي الشَّرَابِ ثَلَاثًا.((مُتَّفق عَلَيْهِ))
Anas (May Allah be pleased with him) reported: The Messenger of Allah (ﷺ) used to breathe three times in the course of a drink (he used to drink in three gulps). [Al-Bukhari and Muslim].
Riyad as-Salihin, 756