وَعَنِ ابْنِ عَبَّاسٍ
أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَسَحَ بِرَأْسِهِ وَأُذُنَيْهِ: بَاطِنَهُمَا بِالسَّبَّاحَتَيْنِ وَظَاهِرَهُمَا بإبهاميه)
The Prophet (sallallahu alayhi wa sallam) wiped his head and also the inside of his ears with his forefingers and the outside with his thumbs. Nasai transmitted it.
Mishkat al-Masabih 382, Book 4, Purification, Hadith 118. 1 min read