It is narrated from Sayyiduna Aws (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) performed ablution and did "istawkafa" three times.
Shu'bah said - and he (the narrator) was an Arab man - I asked him: What does istawkafa mean? He said: "He washed his hands three times."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 598