Re: stick like a bur
I think it depends if you've spend much time trying to get burrs out of your dog's coat or not. I also have Southern relatives, where more colorful expressions might be the norm. So I find this to be a very normal expression. In fact, just yesterday I wrote to someone who owed me some information (we have a friendly relationship so I could tease him) that I was going to be the burr under his saddle blanket until he coughed it up. (I got the information in a couple hours.)
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.