No, the oregano doesn't burn me.
I think I was just swishing too hard, if that makes sense. My muscles just need to get used to it. I'm sure there's no precise method to be swishing, I shish a little and sort of suck in between the front and back of my teeth.
I've learned to just kind of go about my daily routine, or do it in the tub, so that it doesn't seem like forever. I've been able to do 20 minutes now
I might try sunflower oil. Grapeseed oil also seems interesting. I prefer not to use olive oil because I just had a horrible Liver Flushing experience that involved me throwing up 5oz of olive oil that had been sitting in my belly for over 8 hours...mixed with lemon juice.. I also read that it turns your teeth green.
My main battle now is making sure I spit it all. I always seem to get some on the back of my tongue, and I try not to swallow, but sometimes I just have the urge to swallow. I don't swallow the oil, but since some builds up at the back of my mouth, I do swallow that.