I actually discovered that on accident...
What I used to do was sneak out the back door when my family was asleep and if they caught me I was prepared to say "I thought I saw someone cutting through the back yard just went to check it out"

Whatever you do, never admit you were smoking. This one time I was smoking under my covers in bed because I wondered if it would contain the smell...which it didn't. Parents asked what the smell was and I simply said I had no idea what they were talking about.