It is narrated from Sayyiduna Sufyan bin al-Hakam, or al-Hakam bin Sufyan, (may Allah be pleased with him) that whenever the Messenger of Allah (peace and blessings be upon him) performed ablution (wudu), he would take a handful of water and sprinkle it on his private part.
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6362