Pour some water into the mug. Before you perform the trick, you’ll have to experiment with the amount, which will depend on your sponge. The more water that you pour in, the more impressive the trick. But pour in too much, and water will fall out of the cup with the ice.
Utter some magic words, or talk about how your conversation skills sometimes casts a chill over a date.
Turn over the cup and the ice will fall out. You’ll want to take the mug away as soon as possible. If you’re so inclined, you can have a duplicate mug in a bag. When the ice falls out, immediately put your mug into the bag. Later on, you can bring out the duplicate mug, which may be examined.
