Language:
كتاب الحيض
6  
Menstrual Periods
(13)
Chapter: A woman should rub her own body thoroughly during a bath after the menses
(13)
باب دَلْكِ الْمَرْأَةِ نَفْسَهَا إِذَا تَطَهَّرَتْ مِنَ الْمَحِيضِ وَكَيْفَ تَغْتَسِلُ، وَتَأْخُذُ فِرْصَةً مُمَسَّكَةً فَتَتَّبِعُ بِهَا أَثَرَ الدَّمِ
Sahih al-Bukhari 314

Narrated `Aisha:

A woman asked the Prophet (ﷺ) about the bath which is taken after finishing from the menses. The Prophet (ﷺ) told her what to do and said, "Purify yourself with a piece of cloth scented with musk." The woman asked, "How shall I purify myself with it" He said, "Subhan Allah! Purify yourself (with it)." I pulled her to myself and said, "Rub the place soiled with blood with it."

حَدَّثَنَا يَحْيَى، قَالَ حَدَّثَنَا ابْنُ عُيَيْنَةَ، عَنْ مَنْصُورِ ابْنِ صَفِيَّةَ، عَنْ أُمِّهِ، عَنْ عَائِشَةَ، أَنَّ امْرَأَةً، سَأَلَتِ النَّبِيَّ صلى الله عليه وسلم عَنْ غُسْلِهَا مِنَ الْمَحِيضِ، فَأَمَرَهَا كَيْفَ تَغْتَسِلُ قَالَ ‏"‏ خُذِي فِرْصَةً مِنْ مِسْكٍ فَتَطَهَّرِي بِهَا ‏"‏‏.‏ قَالَتْ كَيْفَ أَتَطَهَّرُ قَالَ ‏"‏ تَطَهَّرِي بِهَا ‏"‏‏.‏ قَالَتْ كَيْفَ قَالَ ‏"‏ سُبْحَانَ اللَّهِ تَطَهَّرِي ‏"‏‏.‏ فَاجْتَبَذْتُهَا إِلَىَّ فَقُلْتُ تَتَبَّعِي بِهَا أَثَرَ الدَّمِ‏.‏
Reference : Sahih al-Bukhari 314
In-book reference : Book 6, Hadith 19
USC-MSA web (English) reference : Vol. 1, Book 6, Hadith 311
  (deprecated numbering scheme)