Sunan An-Nasai, Chapter: The Book of Purification

"I would drink while I was menstruating, then I would hand it to the Prophet (saw) and he would put his mouth where mine had been and drink. And I would nibble at a bone on which some bits of meat were left while I was menstruating, then I would give it to the Prophet (saw) and he would put his mouth where my mouth had been." (Sahih)