Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: "The Messenger of Allah (peace and blessings be upon him) offered the aqiqah on behalf of Sayyiduna al-Hasan and Sayyiduna al-Husayn (may Allah be pleased with them both)."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2555