Musnad Ahmad 1153:2364

'Amir ibn Salih narrated to us, he said: Yunus ibn Yazid narrated to us, from Ibn Shihab, from Abu Salamah, from 'Aishah: "That the Messenger of Allah, peace and blessings of Allah be upon him, when he wanted to sleep while he was in a state of major ritual impurity (junub), he would perform ablution (wudu) like his ablution for prayer. And when he wanted to eat or drink, he would wash his hand, then eat and drink."