It is reported about Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that when bathing he would open his eyes and put his finger into his navel.
Al-Tabarani recorded it in al-Mu'jam al-Kabir, and its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطهارة / 1476