Musannaf Ibn Abi Shayba 4:431

Muhammad ibn Fudayl narrated to us, from ‘Ata’ ibn al-Sa’ib, who said: A group of people from the people of Basra testified before me, and with them was al-Hasan ibn Abi al-Hasan al-Basri, from Ma’qil ibn Yasar al-Ashja’i, who said: The Messenger of Allah (may Allah bless him and grant him peace) passed by me while I was being cupped on the eighteenth of Ramadan. He said: "The one who cups and the one who is cupped have broken their fast."