أَخْبَرَنَا قُتَيْبَةُ، عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عَبَّادِ بْنِ تَمِيمٍ، عَنْ عَمِّهِ، أَنَّهُ رَأَى رَسُولَ اللَّهِ صلى الله عليه وسلم مُسْتَلْقِيًا فِي الْمَسْجِدِ وَاضِعًا إِحْدَى رِجْلَيْهِ عَلَى الأُخْرَى ‏.‏

It was narrated from 'Abbad bin Tamim, from his paternal uncle, that he saw the messenger of Allah (PBUH) lying on his back in the Masjid, placing one leg on top of the other. Translation Not Available

Book Ref: Sunan An Nisai Book 8 Hadith 721
Web Ref:  Sunan An Nisai Vol 1 Book 8 Hadith 722