How would you like it if you had ten of these in front of your face all day? Not actually paying any attention or bothering about what you are saying but just going like this. (scroll down for the beautiful .gif)
Repeatedly. Even after you told them to throw that darned thing in the bin.
As from tomorrow, till the day I die, chewing gum is prohibited and only allowed when I expressely say so. It's bad manners to chew with your mouth open too, most of you know this or have learnt it recently.
Kind thanks.
Sorry for the gross cartoon, but that's what my class looked like today. Multiply it by six or ten.