Well, whenever I fall asleep in a place that's not a bed (e.g. at a desk, in a chair, etc.) I have this strange involuntary habit of snapping violently out of my sleep. I basically get a feeling like I'm extremely scared for a split second and then I jerk my head/body up, usually accompanied by a loud screech because my deck slide back a little. I can't help it, I have no idea why this happens. But it's kinda embarrassing sometimes when it happens. Usually I can play it off like I was looking for something lol.
Here's the worst experience of this happening...
We were in history class taking a test, and when I finished there were still some people working so I put my head down and start reading a book. I ended up falling asleep >_> and the next thing I remember was me waking up with a violent jerk, my arms flew in front of me and knocked half the stuff off my desk, and to make things worse I gave a loud "WHOA!" for some reason. All of this happened in like half a second. I looked around and the ENTIRE CLASS was staring at me, including the teacher, who smugly commented "done with your nap?" (I'm sure from everyone else's point of view it was quite hilarious.
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) I didn't say anything for like 10 seconds, I just kept looking around at everybody. Then I picked up the stuff I knocked down and went back to reading my book like nothing happened.
After class my friend kept asking me "Dude what happened? Why'd you do that for?" I didn't really know the answer myself I just said it happens sometime when I fall asleep.