No matter how much you think you should do this, don't. You lay on the desk or lab table and feel really good at first. You only got 3 hours of sleep the night before due to excessive coding/partying, and the sleep deprivation feels like you're being hit over and over by a freight train. You're in the back of the class, odds are the teacher won't see you do it. Laying down, it feels good, you need this. 45 minutes later you're being poked by the kid behind you and you realize that the bell rang 30 seconds ago. You feel like shit now, your body thinks that it has only had 30 minutes of sleep now instead of the 3 hours you had earlier. Your eyes burn, your mouth has a bad taste in it. Please do the responsible thing, eat a large quantity of penguin mints and wait until you can sleep for a good 3 or 4 hours.