If you were taught something different in your school, then please disregard this note.
I was taught that you lay carpet, lay floor tiles, birds lay eggs, and if you're very lucky you get laid when your wife or girlfriend is in the mood; if not, she might tell you not to lay one finger on her.
On the other hand, when you go to bed you lie down, and if you are very unfortunate you can end up lying in a pool of blood. Believe me, I'm not lying to you!