You Irk Me Things That Irk or Annoy Us

I am not sure what I would call this one other than foaming at the mouth. It really irks me when I am talking to someone and they have that white foam starting to accumulate on their lips. It actually makes me totally grossed out. I want to tell them to lick their lips and keep the foamy spit inside their mouth. Is it really that hard to keep your spit inside your mouth so I do not feel like you are going to spit it out on me? I do not understand why it happens with so many people. Then when it starts going on the upper and lower lip and it connects them while they are talking. This is really disgusting. I really want to give them a napkin to wipe it off but how rude would that be?