Is it obligatory to circulate water throughout the entire mouth or reach the furthest depths of the nose during purification?
Chapter on the Obligation of Purification
Al-Mughni
Book of Purification
Primary text
It is not obligatory to circulate water throughout the entire mouth or to make water reach the entirety of the inner nose. That level of thoroughness is a recommended exaggeration (Mubalaghah) for one who is not fasting, as mentioned in the Sunan of Taharah.