I tried to edit my original post, but when I have the cheapo membership, I have to type faster, I guess!
I find that in general, if I have someone picking on me, I call them out right on the spot as bluntly as I can without being rude. I recall once as an CNA I had a coworker pick and pick at me for little things. (SHEESH!)
One situation of mine sticks out. Anyway, one day my boyfriend at the time called me at work. She answered and gave me the phone but then yelled at me that I needed to take the trash out NOW when there was no reason for me to take it out right then...he called for some particular reason that I can't remember. Anyway, I did take the trash out then to avoid a confrontation (bad move on my part), and picked the phone back up. When I was done on the phone, the CNA said, "Gosh, your boyfriend's voice is kind of high, isn't it?" I said, "He has a speech impediment as well. Why don't you pick on that, too?" (He had an issue with saying the R sound. He did indeed have a slight but obvious speech impediment.) She never picked on me from that day forward and was actually nice to me. I don't know if you have anything like that, but I never, ever had anyone try to pick on me quite as personally as that besides my own parents, but that's another story. This CNA was not the only one to pick incessantly at me, but I remember this situation quite well, so that's why I said it.
Some people think they are funny or powerful or something else when they do the incessant picking, but sometimes if you look in their eye and give it right back to them, they will back off.