I love poi too! It's so much fun, but I need to learn some new moves. I have a great DVD but I can't find it after the move :/
Anyway, back to topic...
I would be somewhat cautious about confronting her. Most girls like that won't take it the way you intend, they'll just see you as a jealous girlfriend trying to ruin your boyfriend's fun, if she believes he's actually into it.
Ignoring someone to hope they stop works sometimes, depending on how much they care and how oblivious they are. Some people just don't get it if you're even remotely subtle. And some people are so persistent that even if you say "stop talking to me you crazy bitch" they keep at it.
Is it possible to block individuals from posting on your wall? That would send a pretty strong message! But it's also passive-agressive. I prefer assertiveness, to just outright say "I would like you to stop sending me sexual messages and posting inappropriate comments on my wall. I'm not interested in anything more than friendship with you, and if you can't behave more appropriately, I will have to end this friendship."
Gralson = my husband
Auto = my girlfriend