ENOfficial
Ibn 'Abbas said God’s messenger was lowered gently into the grave head first. Shafi'i transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنِ ابْنِ عَبَّاسٍ قَالَ: سُلَّ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مِنْ قِبَلِ رَأْسِهِ. رَوَاهُ الشَّافِعِي
sunnah.com