Sunan Abi Dawud Book 14, Hadith 155
When the Messenger of Allah (ﷺ) observed I'tikaf, he would put his head near me, and I would comb it. and he entered the house only to fulfill human needs (i.e. to urinate or to relieve himself).
The Prophet (ﷺ) used to observe I'tikaf during ten days of Ramadan every year. But when the year in which he died, he observed I'tikaf for twenty days.
And Yunus also narrated in a similar way from al-Zuhri, and no one supported Malik in his narration from 'Urwah from 'Umrah ; and Ma'mar, Ziyad b. Sad and others have also narrated it from al-Zuhri from 'Urwah on the authority of 'Aishah.