It was narrated that Rubai' bint Mu'awwidh bin 'Afra' said:
"The Prophet performed ablution, and he put his fingers in the (holes) inside of his ears." (RU)
English reference (RU): Vol. 1, Book 1, Hadith 441 (RU)
Arabic reference (RU): Book 1, Hadith 476 (RU)