I came to the Prophet ﷺ from behind. I saw the whiteness of his armpits and he kept his arms away from his sides and raised his stomach (from the ground). (Using translation from Abū Dāʾūd 899)
أَتَيْتُ رَسُولَ اللهِ ﷺ مِنْ خَلْفِهِ فَرَأَيْتُ بَيَاضَ إِبْطَيْهِ وَهُوَ مُجَخٍّ قَدْ فَرَّجَ يَدَيْهِ