The Prophet ﷺ said: Snuff up water freely unless you are fasting.

قَالَ رَسُولُ اللَّهِ ﷺ بَالِغْ فِي الاِسْتِنْشَاقِ إِلاَّ أَنْ تَكُونَ صَائِمًا

[Machine] The Messenger of Allah ﷺ said, "When you make istinja, perform it thoroughly, unless you are fasting, and do not hit your private parts with your right hand as you hit your slaves."

قَالَ رَسُولُ اللَّهِ ﷺ «إِذَا اسْتَنْشَقْتَ فَبَالِغْ إِلَّا أَنْ تَكُونَ صَائِمًا وَلَا تَضْرِبْ ظَعِينَتَكَ كَمَا تَضْرِبُ أَمَتَكَ»

[Machine] "It was narrated that he came to the Prophet ﷺ and mentioned some things, so the Prophet ﷺ said to him: 'Perform a perfect ablution, clean between your fingers, and when you sniff water into your nose, do it thoroughly, unless you are fasting.'"

أَنَّهُ أَتَى النَّبِيَّ ﷺ فَذَكَرَ أَشْيَاءَ فَقَالَ لَهُ النَّبِيُّ ﷺ أَسْبِغِ الْوُضُوءَ وَخَلِّلِ الْأَصَابِعَ وَإِذَا اسْتَنْشَقْتَ فَبَالِغْ إِلَّا أَنْ تَكُونَ صَائِمًا

[Machine] The Messenger of Allah ﷺ said to me, "Trim your fingernails, perform ablution thoroughly, and when you rinse your nose, do so excessively unless you are fasting."

قَالَ لِي رَسُولُ اللهِ ﷺ خَلِّلْ أَصَابِعَكَ وَأَسْبِغِ الْوُضُوءَ وَإِذَا اسْتَنْشَقْتَ فَبَالِغْ إِلَّا أَنْ تَكُونَ صَائِمًا