“Then let them end their untidiness,” and the interpretation of al-Hasan is: The untidiness (al-tafath) is the disheveled state of ihram, and by their stoning [of the pillars].
﴿ثمَّ ليقضوا تفثهم﴾ تَفْسِيرُ الْحَسَنِ: الْتَفَثُ: تَقَشُّفُ الْإِحْرَامِ، وَبِرَمْيِهِمُ