Start out your Sharing Time by asking another member
of the Primary presidency in the back of the room to do something simple
such as turn on the microphone or close the door, etc.
She can respond in an argumentative way and the two
of you can fake an argument.
Hopefully, the children will feel uncomfortable with
the little interchange.
I wouldn't let it go on for very long because the point
is to make them uncomfortable, but not to invite a bad spirit into the
room.
Then you can explain that you did it on purpose so that
they could feel the difference between arguing and peace.
This could easily lead into a discussion about how peaceful
the church usually feels and how much more peaceful the temple is.
You could also discuss how to make their homes feel
more peaceful.