Sahih Bukhari
Prayers (Salat)
Volume: 001 / Book Number: 008 / Hadith Number: 376
Narrates 'Abdullah bin Shaddad:
Maimuna said, "Allah's Apostle was praying while I was in my menses, sitting beside him and sometimes his clothes would touch me during his prostration." Maimuna added, "He prayed on a Khumra (a small mat sufficient just for the face and the hands while prostrating during prayers).