رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 762
The Book About the Etiquette of Eating
Undesirability of Drinking Directly from the Mouth of a Water-Skin
وَعَنْ أبى هُرَيْرَةَ رضى اللَّهُ عَنْهُ قَالَ: نَهَى رَسُولُ اللَّهِ صَلَّى اللَّه عَلَيْهِ وَسَلَّمَ أَنْ يُشْرَبَ مِنْ فِي السِّقَاءِ أو القربة.((مُتَّفَقٌ عَلَيْهِ))
Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah (ﷺ) prohibited drinking directly out of the mouth of a water- skin. [Al-Bukhari and Muslim].
Riyad as-Salihin, 762