My 8 month old is a wiggly, wiggly baby. While breastfeeding she tries to crawl, climb, or otherwise use me as a jungle gym. Not all the time but frequently enough. I'm tired of it and so are my nipples.

Any suggestions as to how to get her to stay still?

My two were active breastfeeders at times too. It helps if you minimize distractions while the baby is nursing so that she's not trying to see whatever is going on around her - make nursing a quiet activity.
I also found that mine were squirmiest when they weren't really hungry and were just sort of nursing because it was there. That might not be an issue for you, but it was sometimes for me, and distracting the baby until she really wanted to nurse helped minimize the wiggly nursing.

My baby can be squirmy too. Even though he seems too old for it, I find that using a boppy helps keep him in place. I still don't use it every time but when I do he's more still. HTH

Thanks for the suggestions. I'll try them and see if they help.

I have started ending the nursing session as soon as she starts up - resulting in lots of tears and wailing. However, she already skinny - I don't want her to go hungry or to encourage a nursing strike.