Sahih Muslim
The Book of Menstruation (Kitab Al-Haid)
Book Number: 003 / Hadith Number: 623
'A'isha reported: When the Messenger of Allah (may peace be upon him) took a bath because of sexual intercourse, he called for a vessel and took a handful of water from it and first (washed) the right side of his head, then left, and then took a handful (of water) and poured it on his head.