You definitely don't want to stick it up your nose.
Just hold it straight up, the liquid cream will be at the bottom, and the first few seconds, will spray only the nitrous. So you put it in your mouth, spray in the air, and then breathe it down. Then when the cream starts to go in your mouth, just seperate it from the air, or let go of the whip cream. Then you just sit there, and hold your breath. You'll start to feel a little dizzy at first, then you start feeling this strong pulsating feeling all over. Most people take two hits back to back. With enough nitrous, its like being taken away for a few seconds, and your thoughts are a little puzzled. Then when you start to come back, you're not really sure where you are, what you were doing. And then after you're done, you sit there and suck out the left over whip cream for desert. I'm getting a head ache just thinking about it.