People keep talking about the size your hands need to be to do this successfully. This is no
different than any other skill involving misdirection. If you get your spectators looking in the
right place, you could get away with putting anything in the cup. A great effect that, if done
properly, gets fantastic reactions. Certainly takes practice, but for sure worth it. If anyone wants
to see what a good version looks like, check out Paul Daniel's rendition.