AIBU to want to throttle my father?

[2holibobssofar]

I’m visiting family and for the last 2 hours my dad has been opening and closing his mouth, making horrible wet smacking noises every few seconds.
He’s reading a book, no reason for it, it’s just a really horrible thing he sometimes does.
The TV is on, but I can still hear it. I’m actually going to have to kill him!

My late ex-mother-in-law had a habit that used to drive me up the wall! She had very long fingernails and she used to click them all the time. I put it down to her living on her own and not realising she was even doing it. However it doesn't sound as if he is on his own? It could be something to do with dentures, if he wears them.