Abu Dawud Book 5, Hadith Number 2161.

Narated By ‘Aisha, Ummul Mu’minin : I and the Apostle of Allah (PBUH) used to lie in one cloth at night while I was menstruating. If anything from me smeared him, he washed the same place (that was smeared), and did not wash beyond it. If anything from him smeared his clothe, he washed the same place and did not wash beyond that, and prayed with it (i.e. the clothe).