I'm pretty careless about getting caught, but what I do is lock my door, close my blinds, and light an incent. I smoke, put everything away and clean up well. Some times when I'm done i'll put on the fan and spray air freshener, I usually just dont care. I keep all my stuff in my desk drawer in a fanny pack type thing. Some kids are waaaaaay to paranoid. It's not that tough to get rid of the smell.