"When the Messenger of Allah ﷺ prostrated, he would hold his arms out to his sides, so that the whiteness of his armpits could be seen from behind. And when he sat he rested on his left thigh."  

كَانَ رَسُولُ اللَّهِ ﷺ إِذَا سَجَدَ خَوَّى بِيَدَيْهِ حَتَّى يُرَى وَضَحُ إِبْطَيْهِ مِنْ وَرَائِهِ وَإِذَا قَعَدَ اطْمَأَنَّ عَلَى فَخِذِهِ الْيُسْرَى