It is narrated from Sayyiduna Ka'b bin Ujrah (may Allah be pleased with him) that he said: "I saw the Messenger of Allah (peace and blessings be upon him) eating with his three fingers, namely the thumb, the finger next to it and the middle finger. Then I saw him (peace and blessings be upon him) licking those three fingers of his before wiping (his hand); he (peace and blessings be upon him) would first lick the middle finger, then the one next to it, and then the thumb."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Ibn Jurayj (may Allah have mercy on him) except Abd al-Majid (may Allah have mercy on him)."
Hadith Referenceالمعجم الأوسط / باب الألف / 1649
Hadith Gradingمحدثین:فيه الحسين بن إبراهيم الأذني ومحمد بن كعب بن عجرة لم يُعرفا، وبقية رجاله ثقات
Hadith Takhrij«قال الهيثمي: فيه الحسين بن إبراهيم الأذني ومحمد بن كعب بن عجرة ولم أعرفهما وبقية رجاله ثقات «مجمع الزوائد ومنبع الفوائد، ج 5، ص 28»»