Sayyiduna Mu'awiyah (may Allah be pleased with him) showed them the ablution (wudu) of the Messenger of Allah (peace and blessings be upon him). When he reached the wiping of the head, he placed both his palms on the front of his head, then moved them back until he reached the nape of the neck, then brought them back to the same place from where he had begun.
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 16935