It's your place too and she should recognize that! How uncomfortable do you have to feel in your own place before she realizes what is going on is rude?!?!?!
I'd sit her down and say LOOK HERE... there are going to be some rules to live by or else you're going to have to find a new roommate. Don't make the rules so insane that she thinks of you as her mother...but the nekkid boyfriend on the couch!!!!!!!!!!
I'm having a problem myself because my roommate has a cat in our appartment and we're not supposed to. The other problem is I'm severly allergic to it and she doesn't seem to care. But my BIGGEST problem is that the damn cat has puked on the carpet in the living room and in her room. I'm going to tell her that if we risk loosing our downpayment due to the cat, she can pay me my half because it's not my fault that her cat ate tinsel!
URG!!!!!!!!!