Hadith: I used to sleep in front of the Messenger of Allah (may Allah's peace and blessings be upon him) with my legs in his prayer direction. When he wanted to prostrate, he would prod me so that I withdraw my feet, and when he stood up, I would stretch them. In those days, houses had no lamps

عن عائشة رضي الله عنها قالت: «كنت أنام بين يَدَيْ رسول الله صلى الله عليه وسلم ورِجْلايَ فِي قِبْلَتِهِ، فإذا سجد غَمَزَنِي، فقَبَضتُ رِجْلَيَّ، فإذا قام بَسَطْتُهُمَا، والبيوت يومئذ ليس فيها مصابيح».
[صحيح] - [متفق عليه]

‘Ā’ishah (may Allah be pleased with her) reported: I used to sleep in front of the Messenger of Allah (may Allah's peace and blessings be upon him) with my legs in his prayer direction. When he wanted to prostrate, he would prod me so that I withdraw my feet, and when he stood up, I would stretch them. In those days, houses had no lamps.
Sahih/Authentic. - [Al-Bukhari and Muslim]

Explanation

‘Ā’ishah (may Allah be pleased with her) said that she used to sleep in front of the Prophet (may Allah's peace and blessings be upon him) when he was praying at night. Due to the narrowness of their home, she would stretch her legs between him and his place of prostration. As long as the Prophet stood praying, ‘Ā'ishah would stretch her feet. When he wanted to prostrate, he would prod her to withdraw her feet. If she had been able to see him sitting down to prostrate, she would have withdrawn her feet by herself, and there would have been no need for poking. However, there were no lights at their home at that time, thus she was not able to see the Prophet and save him the trouble of having to prod her.