Muhammad bin Sirin said: I washed Sayyiduna Anas bin Malik (may Allah be pleased with him) (for burial). When I reached his private parts, I said to his sons: You have more right to wash your father's private parts; wash them yourselves. So the one who washed them wrapped a cloth around his hand, and a cloth was lying over the private parts; then he washed the private parts from beneath the cloth.
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 710