[Thanks to a thread from Facebook for letting me know about this one]
Suetonius Tranquillus, Peri Blasphemon 11.12
“According to Hipponax [fr. 114c] the “messêgudorpoxéstês” is one who often relieves himself during a meal so that he may fill himself up again”
<Κατὰ δὲ ῾Ιππώνακτα (fr. 114 c Masson), καὶ ὁ> μεσσηγυδορποχέστης, ὁ μεσοῦντος τοῦ δείπνου πολλάκις ἀποπατῶν, ὅπως πάλιν ἐμπίπληται ὁ αὐτός.
For the word-builders: messêgu (“in the middle of”) + dorpos (“dinner, meal”)+ khestês (a nomina agentis—agentive noun—from the Greek verb χέζω, “to shit”).
And another from the Walters Art Museum: