Answered by Shaykh Yusuf Weltch
How does one perform istinja’ during fasting? To what extent does one’s fast break via the water of istinja’?
In the Name of Allah, the Most Merciful and Compassionate
Water Entering the Vagina During Fasting
For the female front private area, it is sufficient to wash within the outer labia without inserting water into the actual vaginal opening.
If water did enter the vaginal opening, the fast is still intact as long as the water did not reach the length of a mihqana (a vaginal syringe sometimes used for douching). [Tahtawi/Shurunbulali, Hashiyat Maraqi al-Falah]
Water Entering the Anus During Fasting
Washing one’s rear private part does not require water to enter the anus. It is sufficient to wash the exterior of the anus. [Ibid.]
If water does, however, enter the anus, the fast is valid as long as the water does not reach the length of a mihqana (a rectal syringe: a tool used from enemas). [Shurunbulali, Maraqi al-Falah]
It is highly unlikely that water would reach this distance from a normal istinja’. It is, however, recommended as a caution to dry one’s anal area before standing. [Ibid.]
Hope this helps
Allah knows best
[Shaykh] Yusuf Weltch
Checked and Approved by Shaykh Faraz Rabbani
Shaykh Yusuf Weltch teaches Arabic, Islamic law, and spirituality. After accepting Islam in 2008, he completed four years at the Darul Uloom Seminary in New York, where he studied Arabic and the traditional sciences.
He then traveled to Tarim, Yemen, where he studied for three years in Dar al-Mustafa under some of the most outstanding scholars of our time, including Habib Umar Bin Hafiz, Habib Kadhim al-Saqqaf, and Shaykh Umar al-Khatib.
In Tarim, Shaykh Yusuf completed the memorization of the Quran and studied beliefs, legal methodology, hadith methodology, Quranic exegesis, Islamic history, and several texts on spirituality. He joined the SeekersGuidance faculty in the summer of 2019.