I've never done it intentionally, but as someone who occasionally has lucid dreams #2 definitely seems accurate. Much of the time I lucid dream it's when I'm sleeping extremely lightly right before I wake up.

In fact, I know that I'm dreaming and that if I open my eyes (somehow separate from opening or closing my eyes in my dream) I will wake up. Sometimes I might shout or say something in my dream and I actually say it out loud and that wakes me up as well.