Lurkey writes:
Thought i'd share.
I think I will avoid that technique, thanks.
But if anyone would like to know a more sanitary cure, here it is: Ask a simple maths question.
You don't want it too easy - e.g. 4 + 4; they won't have to think - they already know the answer by rote.
You don't want it too hard - e.g. 6432 / 327; they will just refuse to do it.
You want a questions slightly trickier than easy - e.g. 17 x 8
(If they are good at mental arithmetic then you may have to add an extra digit.)
There are different questions your could ask, but maths questions can be "self administered".
"There is no great invention, from fire to flying, which has not been hailed as an insult to some god." J. B. S. Haldane