Sahih Bukhari Volume 3, Book 30, Hadith 1930

حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا يَحْيَى، عَنْ هِشَامِ بْنِ أَبِي عَبْدِ اللَّهِ، حَدَّثَنَا يَحْيَى بْنُ أَبِي كَثِيرٍ، عَنْ أَبِي سَلَمَةَ، عَنْ زَيْنَبَ ابْنَةِ أُمِّ سَلَمَةَ، عَنْ أُمِّهَا ـ رضى الله عنهما ـ قَالَتْ بَيْنَمَا أَنَا مَعَ، رَسُولِ اللَّهِ صلى الله عليه وسلم فِي الْخَمِيلَةِ إِذْ حِضْتُ فَانْسَلَلْتُ، فَأَخَذْتُ ثِيَابَ حِيضَتِي فَقَالَ ‏"‏ مَا لَكِ أَنُفِسْتِ ‏"‏‏.‏ قُلْتُ نَعَمْ‏.‏ فَدَخَلْتُ مَعَهُ فِي الْخَمِيلَةِ، وَكَانَتْ هِيَ وَرَسُولُ اللَّهِ صلى الله عليه وسلم يَغْتَسِلاَنِ مِنْ إِنَاءٍ وَاحِدٍ، وَكَانَ يُقَبِّلُهَا وَهُوَ صَائِمٌ‏

Narrated By Zainab : (Daughter of Um Salama) that her mother said, "While I was (lying) with Allah's Apostle underneath a woollen sheet, I got the menstruation, and then slipped away and put on the clothes (which I used to wear) in menses. He asked, "What is the matter? Did you get your menses?" I replied in the affirmative and then entered underneath that woollen sheet. I and Allah's Apostle used to take a bath from one water pot and he used to kiss me while he was fasting."