Whenever I have a stomachache (whether anxiety-induced or otherwise), I touch my mouth with a terrycloth towel in order to see if it will make me vomit. This is because I used to vomit into terrycloth towels when I was a child. The reason I do this ritual is because I go by Bill Murray's logic in What About Bob - "If I fake it, then I don't have it" (hope that makes some kind of sense)
Related to the above, when I have a stomachache, I will also open up my windows or go outside to breathe fresh air. This is because when I was nauseous as a child, my parents took me outside and told me that the fresh air would help.
I run around in a pattern while listening to music. This is because this is the best way to get lost in my imaginary world, and also because I get restless sometimes.
Sometimes while reading, if I find myself not paying attention, I will re-read the passage I just read, sometimes several times in a row, just to make sure I've "absorbed" it.
I have an imaginary world that includes all of my favorite characters from whatever shows and movies I'm obsessed with at a given time. I love to pair them off into couples and make up children for them.