Oh my, tmi for me!!!

So I'm currently in high school, I will be finished in one and a half years- hooray! However, that means that I live with my parents. That's not necessarily bad, however my house has paper-thin walls... And my mother has a birth control coil thing... So I know what they do when they do it... Basically, I am traumatized several times a month. What do I do?!?!? I am seriously disgusted! I know it's natural, but come on, they're my parents... Anyone ever had this issue? My brother moved out of his room which is right next to mine, but is not attached to theirs. However, when my mom asks why I'm moving to his room, what am I going to say? "The walls are paper thin"?!?!? Please, please help me. I've had enough!!!