Malik bin Dinar relates:
The Prophet (S) never ever filled his stomach with bread, nor with meat except in the situation of dafaf. Malik bin Dinar asked a Bedouin man: What is dafaf? He responded: That he would eat with the people. (ID)
English reference (ID): Book 9, Hadith 68 (ID)
Arabic reference (ID): Book 9, Hadith 72 (ID)