"The Prophet wiped over the Khuff and its bottom."
Jami` at-Tirmidhi Book 1, Hadith 97
← Previous Hadith 'When we were traveling, Allah's Messenger would order us not to remove our Khuff for three days and nights, except for Janabah, but not for defecating, urinating, and sleep."

Jami` at-Tirmidhi Book 1, Hadith 96 Next Hadith → "I saw the Prophet wiping over the Khuff: on the tops of them."

Jami` at-Tirmidhi Book 1, Hadith 98