Musnad Ahmad 1153:2162

Uthman ibn Umar narrated to us, he said: Malik narrated to us, from Salim Abu al-Nadr, from Abu Salamah, from Aisha, she said: "The Messenger of Allah (peace and blessings of Allah be upon him) used to pray while my legs were in the direction of his Qiblah. When he wanted to prostrate, he would nudge me, so I would draw them in, and when he stood up, I would stretch them out."