Roommate Advice

Okay, so I have three other roommates and we all get along great and everything. But, my one roommate, who I actually went to HS with, ALWAYS has her bf over. Like... every day. And he’s rude and leaves his mess and pretty much acts like he lives here, even though he goes to college in the same town as us. It’s been frustrating for at least two of us because we don’t feel like we can just relax in our home. Especially when they’re all over each other in the living room, like keep it in your bedroom plz. Idk. I needed to rant and I’m not sure how to approach talking to her about it. Any advice is greatly appreciated.