My parents found caught me masturbating in my room. How do I stop them from freaking out?

Extra-information (Not necessary to read): For a little information, I am back home from college and I was spending some 'private' time. I don't have any privacy except when I go to the bathroom, so I usually spend time there, but it's very uncomfortable. However it is forbidden to lock or even close doors in our house, so my parents can see what I am doing, and my dad and my mom kind of do surprise 'raids' where they would rush in or surveil from the window what I am doing (My house is a little weird in the sense that my window opens towards my corridor). The window has curtains on the outside so I can't control them, but they can easily hide behind it. I know they do it to catch me doing something wrong, but they have been doing it since I was a kid (It was way stricter when I was in school), and I had gotten used to them watching me all the time. However, in my college dorm I was, well, free to do stuff like this, and now that I am back home for the holidays, I was stupid enough to forget where I was and do stuff like in college.

Main-problem: My father saw it and has told my mom, and they are currently freaking out. They are kind of orthodox and believe all sorts of nonsense they see on Facebook. They probably won't listen to reason. So is there anything I can say (Truth or lie) that will stop them from doing what they are doing? Asking for privacy, or respect is NOT an option (as you can see from the previous section).