Answered by Shaykh Faraz Rabbani
It says in an English translation of ‘Nur al-idha’ in the Taharah section that: “A person not fasting should fully relax his hips so that the filth in the orifice may be removed fully. A fasting man, however, must not do this in case the water used enters and thus corrupts his fasting. On completion of cleanliness with water, a person will wash his hands a second time and, if he is fasting, dry his hips before standing up, in case the water still present at the genitals or the anus enters, thereby corrupting his fasting. This drying is also ‘praiseworthy’ for one not fasting.” Can you please explain/comment on this the drying bit in reference to the fast and its corrupting?
This drying is a precautionary move, because the fast would only be invalidated if a drop of water went up the rectum to the extent that a suppository does with certainty, which, as Imam Tahtawi commented, is very unlikely.