Ayesha said, "I never wished to be in the place of any woman more than Sawda bint Zama, despite her sharp temper."She added, "When she grew old, she gave her day with the Messenger of Allah ﷺ to me." Sawda said, "Messenger of Allah, I have given my day with you to Ayesha." So the Messenger of Allah ﷺ would allot two days to Ayesha, her own day and Sawda's day.
ما رأيت امرأة أحب إلي أن أكون في مسلاخها من سودة بنت زمعة من امرأة فيها حدة، قالت: فلما كبرت جعلت يومها من رسول الله ﷺ لعائشة، قالت: يا رسول الله، قد جعلت يومي منك لعائشة، فكان رسول الله ﷺ يقسم لعائشة يومين: يومها، ويوم سودة.
Bukhari narrated it in the Book of Marriage (5212), and Muslim in the Book of Suckling (1463:47), both through the route of Hisham bin Urwa, from his father, from Ayesha, and he mentioned it, and the wording is Muslim's.Her saying, "in her sloughed-off skin," means in her very skin, and the sense is that I should be her.