how we did it:
1)catch a fly and put into a bottle or container
2)get a string about a meter long (sewing string is best)
3)put in freezer for 10-15 mins
4)take fly out and tie string around the neck part(not too tight though)
5)double tie the string
6)then dunk in warm water quickly and then let the fly sit
7) about a minute later the fly should be thawed out if not then you left it in the freezer
too long or let the fly sit longer
8) go smoke up
9) come back and shake fly around and he'll start buzzing around
10) LAUGH YOUR BRAINS OUT!!!!!!!!!!!!!!!!