Your teacher has bad timing.

Just explain the situation and you should be fine.

Lmao... I'm sure the teacher thought you just got up on the wrong side of the bed today....

Just do your best Ralph Wiggum impression and you'll be fine.

Getting angry isn't usually the best way of getting someone to stop annoying you as most of the time they are looking for a reaction, you gotta do some dead pan cold hearted remark like "if you touch me again i will cut off your fingers"

Saw an FML like this before only instead of slapping the hand, it was an elbow to the stomach, and the teacher was the principal

This all reminds me: When I was younger I accidentally dropped my jacket in the staircase area where it flew down two flights of stairs and landed on the assistant principals head (who I was terrified of.) I remember trying to causally walk by and acting like I had no idea who dropped the jacket when she was screaming. Wow. Fifth grade was tough.