I agree with DreamSparrow (?) on the body fluids, the stupid settings (yes, so very true!), the flick-tongue kissing, and the lack of believable kissing. The thoughts on the gagging/male domination thing deserve further discussion. Part of the reason why I think it is taboo (to some degree) in mainstream media might be because it's much more common for men to abuse their status or power (physical or otherwise) to wrong women in some way than it is vice-versa - although that is hardly unheard of.
Another one I'd like to add to the list is when the guy(s) hold open the woman's mouth with their hands/fingers or some dental apparatus before they cum in her mouth or whatever. Strikes me as gross, foul, offensive or a combination of all three, depending. Also, when gagging or deepthroating becomes some extreme challenge to see how much drool can pour out of her mouth, or back into her nose, or how much her make-up can run and make her look like some depressed psycho-clown, well, that's hardly a turn-on, either. But just to see a little deepthroating, with a little drooling and a little gagging/coughing, well that can be pretty arousing (here I'm thinking Belladonna or Veronica Vanoza, for example).... Not like - "hey look, she drooled 3 gallons of saliva and now she's badly dehydrated!" - lame!
Another one I'd like to add to the list is when the guy(s) hold open the woman's mouth with their hands/fingers or some dental apparatus before they cum in her mouth or whatever. Strikes me as gross, foul, offensive or a combination of all three, depending. Also, when gagging or deepthroating becomes some extreme challenge to see how much drool can pour out of her mouth, or back into her nose, or how much her make-up can run and make her look like some depressed psycho-clown, well, that's hardly a turn-on, either. But just to see a little deepthroating, with a little drooling and a little gagging/coughing, well that can be pretty arousing (here I'm thinking Belladonna or Veronica Vanoza, for example).... Not like - "hey look, she drooled 3 gallons of saliva and now she's badly dehydrated!" - lame!