(Imām Bukhārī narrates): Muslim narrated to us, he said: Wuhaib narrated to us, he said: Mansur narrated to us, from his mother, from Hazrat Aisha (may Allāh be pleased with her), that
a woman of the Ansar said to the Prophet ﷺ: How should I bathe from menstruation? He said: Take a piece of musk and purify yourself with it three times. Then the Prophet ﷺ turned his face away out of shyness — or he said: purify yourself with it — then I took hold of her and pulled her toward me and told her what the Prophet ﷺ meant.
حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ، قَالَ: حَدَّثَنَا وُهَيْبٌ، حَدَّثَنَا مَنْصُورٌ، عَنْ أُمِّهِ، عَنْ عَائِشَةَ
أَنَّ امْرَأَةً مِنَ الأَنْصَارِ قَالَتْ لِلنَّبِيِّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ: كَيْفَ أَغْتَسِلُ مِنَ المَحِيضِ؟ قَالَ: "خُذِي فِرْصَةً مُمَسَّكَةً، فَتَوَضَّئِي ثَلاَثًا". ثُمَّ إِنَّ النَّبِيَّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ اسْتَحْيَا، فَأَعْرَضَ بِوَجْهِهِ، أَوْ قَالَ: "تَوَضَّئِي بِهَا". فَأَخَذْتُهَا فَجَذَبْتُهَا، فَأَخْبَرْتُهَا بِمَا يُرِيدُ النَّبِيُّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ.
Reference: Sahih Al Bukhari 315