The One with the Boobies - S1-E13
Corrected entry: In the coffee house when Joey's dad asks Ross "How's the wife?" he moves his head and makes a groaning sound. His lips do not visibly move, and there is no other indication that he made this noise. It also sounds strange and misplaced in the shot if you listen to it in surround sound, implying it was dubbed in afterwards. (00:04:10)
Correction: The sound that Ross makes is perfectly possible as his mouth is slightly open. You don't need to move your lips to groan.
Dwarf