Earthquake Mode

I just recently inherited my sister's cell phone. I am still learning the rules and practices of cell phones, and today a rather funny incident occurred.
I was sitting in my history class, my phone in my pocket on vibrate. I usually have my phone on vibrate just cause I don't like ringtones. Anyway, it was in my pocket, and I was completely absorbed in my class. We were talking about Charlesmagne and I was engrossed, as well as madly taking notes. When, quite out of the blue, someone called me. Now what you have to understand is that I am
a)Still getting used to having something shake in my pocket
b) Actually in a different century, picturing Charlesmagne murdering his brother
I was so surprised by this sudden quaking, I gasped, jumped a few feet and collided with the table, and threw my pencil in the air all in one seamless motion.
Everyone turned to look at me. I mean everyone. My prof stopped speaking and asked me if I was okay. Red-faced, I nodded and dug out my phone to see who had called me; pretending that jumping up in the air and throwing pencils was a perfectly ordinary thing to do.
What can I say? Vibrate mode hurts.