Musnad Ahmad 1153:586

Hashim ibn al-Qasim narrated to us, he said: al-Mubarak narrated to us, he said: My mother narrated to me, from Mu'adhah al-'Adawiyyah, from 'Aishah, that she informed her, she said: "I used to perform ghusl, I and the Messenger of Allah, may Allah bless him and grant him peace, from a single vessel, and I would say to him: 'Leave some for me, leave some for me.'"