How do I stop my friend from chamber lurking if she's not on my friends list?

I have a friend I met on the internet, and its entirely possible she is using my profile to gain access to chambers (mostly NSFW ones) she doesn't have enough karma for YET.<br> She knows my account information. How do I prevent her from doing this if I don't want to remove her from my friends list entirely, but she needs to be removed from my profile???