He saw the Prophet ﷺ sitting during the prayer. He lay his left foot on the ground and placed his forearms on his thighs, and pointed with his forefinger, supplicating with it. (Using translation from Nasāʾī 1264)  

أَنَّهُ رَأَى النَّبِيَّ ﷺ «جَلَسَ فِي الصَّلَاةِ فَفَرَشَ رِجْلَهُ الْيُسْرَى وَوَضَعَ ذِرَاعَيْهِ عَلَى فَخِذَيْهِ وَأَشَارَ بِالسَّبَّابَةِ يَدْعُو»