Abu Dawud Book 1, Hadith Number 166.

Chapter : Sprinkling water on private parts of the body after ablution.

Narated By Hakam ibn Sufyan ath-Thaqafi : When the Messenger of Allah (PBUH) urinated, he performed ablution and sprinkled water on private parts of the body.

Abu Dawud said: A group of scholars agreed with Sufyan upon this chain of narrators. Some have mentioned the name of Sufyan b. al-Hakam, and others al-Hakam b. Sufyan.