Abu Dawud Book 7, Hadith Number 2361.

Narated By Thawban : The Prophet (PBUH) said: A man who cupped and a man who has himself cupped broke their fast. The narrator Shayban said in his version: AbuQilabah told me that AbuAsma’ ar-Rahbi told him that Thawban, the client of the Apostle of Allah (PBUH), told him that he heard the Prophet (PBUH) say this.