A few questions from a newbie

Hi! This site is fantastic,...I have already learned a lot. However I have a couple questions before I start.
First of all...I thought OP whitens teeth but I just read how OO (Olive-Oil) can make them yellow. My teeth stain easily so i am concerned and confused as to the contradiction in results. Coconut oil was suggested....should I start with that? I do have bad Acne though, wondering if Coconut oil would be worse for that.
Also...what about the swallow reflex? Is it possible to swallow at the back of the throat while swishing and will the tongue block stuff from accidentally going down? I think this last question sounds odd but I am curious.
Thank you!