It is narrated from Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) that the siwak used to be on the ear of the Prophet (peace and blessings be upon him) just as a pen is on the ear of a scribe.
(b) Abu al-Qasim (al-Tabarani) said: Only Yahya narrated it from Sufyan. The Shaykh said: Yahya bin Yaman is not strong according to the scholars of hadith, and it seems that he made a mistake, carrying over the earlier hadith of Muhammad bin Ishaq to this one.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 157