Apart from THAT scene in "When Harry met Sally", I absolutely hate any sounds that adults make while eating that are anywhere near the sounds that their - or anyone else's - partner might conceivably make whilst having sex.
It is bad enough if my DH makes any sort of sounds when we are eating alone, but if we are in a group - related or not, but even worse if they are related to me - and someone makes those sounds, particularly the wet slurping type of sounds, then I just want the ground to open up and swallow me (sorry, no pun intended), as I am so embarrassed thinking that it has made the rest of the group squirm in their seats, whilst imagining the person "Mmming and Ahhhing" making those sounds while giving or receiving oral sex!
My own DH is an open mouthed chomper. I can only eat with him if we have music on, or are watching TV, or if we are in some sort of noisy environment. After many years together I have only recently plucked up enough courage to ask him to please close his mouth while he is chewing chewing gum. I have had to remind him several times, but he does seem to be getting the idea at last.
Again whilst eating on our own, I have said "oh, I can see the inside of your bellybutton" - unfortunately that doesn't seem to be working, so I might have to say in either a much more serious voice "I can see the inside of your bellybutton, and the mushed up contents of your stomach, and it is not a pleasant sight", or say in a much more Mumsnetty manor "FFS, you have been driving me, and more importantly, anyone else who has to eat with you, slightly insane. It is revolting hearing you, and seeing into your mouth whilst it has a mixture of mushy food slicked around it, so please either eat politely, or eat on your own.