So people don;t have to look it up themselves:
Volume 5, Book 57, Number 119:
Narrated Hisham's father:
The people used to send presents to the Prophet on the day of 'Aisha's turn. 'Aisha said, "My companions (i.e. the other wives of the Prophet) gathered in the house of Um Salama and said, "0 Um Salama! By Allah, the people choose to send presents on the day of 'Aisha's turn and we too, love the good (i.e. presents etc.) as 'Aisha does. You should tell Allah's Apostle to tell the people to send their presents to him wherever he may be, or wherever his turn may be." Um Salama said that to the Prophet and he turned away from her, and when the Prophet returned to her (i.e. Um Salama), she repeated the same, and the Prophet again turned away, and when she told him the same for the third time, the Prophet said, "O Um Salama! Don't trouble me by harming 'Aisha, for by Allah, the Divine Inspiration never came to me while I was under the blanket of any woman amongst you except her."
remember, Muhammad is over 50 at this point, and Aisha is 9.