Sahih Bukhari Volume 8, Book 74, Hadith Number 293.

Narated By ‘Aisha : Allah’s Apostle used to offer his prayer (while standing) in the midst of the bed, and I used to lie in front of him between him and the Qibla It I had any necessity for getting up and I used to dislike to get up and face him (while he was in prayer), but I would gradually slip away from the bed.