Sahih Muslim | Book 3 | Hadith Number 626
Narrated by Abu Salamab. 'Abd al-Rahman
Abu Salamab. 'Abd al-Rahman reported: I along with the foster brother of 'Aisha went to her and he asked about the bath of the Apostle (may peace be upon him) because of sexual intercourse. She called for a vessel equal to a Sa' and she took a bath and there was a curtain between us and her. She poured water on her head thrice and he (Abu Salama) said: The wives of the Apostle (may peace be upon him) collected hair on their heads and these lopped up to ears(and did rot go beyond that).