Give Life Advice

Hey guys,

My roommate came over today with 3 friends. One is her boyfriend, the other two are strangers to me. That's cool, obviously, she can do that. The issue starts when she and her bf leaves:

She says she'll be back in 15 min, and that her two other friends will stay in her room while she's out. I say, "ok." She's gone. I can hear them playing Smash Bros while I study. After about 20 minutes, the game music stops and I hear a bed creaking. Then- Constant. Freaking. Moaning. I go to my room to at least get my headphones to try to block the sound out, but then I hear it even louder with a lot of dirty talk.

I knocked on the door to ask her friends to be more quiet but idk if they even heard me. My roommate came back with her bf after like an hour and I felt super uncomfy for the rest of the day. Any advice so it doesn't happen again?

TL;DR: Roommate left her friends over and they banged loudly. Idk if I'm supposed to tell her or not...