Ok so I tend to have lucid dreams if I take a nap in the middle of the day. Just today I had a very lucid dream, I was floating around in my room.. trying to keep myself from getting to excited and I decided I wanted to go outside. As i flew through my windows my dream ended.. The window was closed and I tried going through it, can I not pass through objects in a lucid dream?

Also what are some techniques to keep myself from waking up?