I don't have any triggers myself, and I understand sometimes the oddly mundane things being the things that squick you out, but I don't think every single thing that could possibly squick someone should have to be outlined before the reading begins. Sometimes, completely consensual vanilla heterosexual sex weirds me out if it's wrong for the characters involved.

I do like how AO3 gives you the level of warning you want to give, or to just tag things to make for easy searching. I sort of wasted an entire day a couple of weeks ago going through the mpreg tag >.>

The fic I wrote that pushed me involved breast feeding lol. I am a woman, have boobs, and it's just something that has always made my skin crawl at the thought of/sight of, so working through it and writing it in a way that was hot and intimate to me was a challenge.