Sunan An-Nasai, Chapter: The Book of the Qiblah

"I heard Aishah say: 'The Messenger of Allah (saw), Abu Al-Qasim, and I were beneath a single blanket, and I was menstruating. If something got on him from me, he would wash whatever had got on him and he did not wash anywhere else, and he prayed in it then came back to me. And if anything got on him from me, he would do exactly the same and he did not wash anywhere else.'" (Hasan)