How do you open a door with a paperclip?

Well, I always thought that you could just stick it in and it would work, but that DIDN'T work/. I stuck i in and leaned it to the right, and my sister (who was on the other side of the door)said that it was unlocked. Fortunately, I couldn't do it again. :( And while I answered this, my sister unlocked the door with a paperclip. She did it again. :(