“When anyone of you drinks, let him not breathe into the vessel. If he wants to continue drinking, let him move the vessel away (in order to breathe) then bring it back, if he wants.”  

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا شَرِبَ أَحَدُكُمْ فَلاَ يَتَنَفَّسْ فِي الإِنَاءِ فَإِذَا أَرَادَ أَنْ يَعُودَ فَلْيُنَحِّ الإِنَاءَ ثُمَّ لْيَعُدْ إِنْ كَانَ يُرِيدُ  

“The Messenger of Allah ﷺ forbade breathing into the vessel.”  

نَهَى رَسُولُ اللَّهِ ﷺ عَنِ التَّنَفُّسِ فِي الإِنَاءِ