This disappearing trick is one of the best impromptu vanishing acts that I've ever seen. It never fails to get a gasp of disbelief from the spectators, but it does take a lot of practice to get right.
It's a relatively simple idea. You're at a dinner party, and because it's your night off, you've left all your props at home. But news that you can "do magic" has traveled further among your friends and acquaintances than you thought was possible.
Before long, people have finished eating and they want to be entertained. So they start saying "go on, show us some of your magic". One voice becomes two and before long the whole company is expecting a performance.
What can you do? You don't have any props, but you don't want to be seen as a bore. So you pick up your glass of wine and take a long sip as though trying to remember a good trick. Once your glass is half empty (or half full depending upon how optimistic you feel), you appear to throw your glass up at the ceiling, but nothing comes back down and your hand is empty.
A gasp travels around the room.
You've made your glass and the wine in it disappear right under their noses. They weren't expecting your magic show to begin so suddenly.
Moments later, after the full impact of your illusion has taken effect, your glass of wine is found inside the coat of the person sitting next to you.
How did you do it?
You start by adding something to the conversation so that everyone is looking at you. Ideally, this should be something that really gets their attention and leaves them waiting to hear what you have to say. Then, as you raise your glass to drink with your right hand, make sure your feet are flat on the ground a few inches apart and your left hand is on your left knee holding your napkin ready.
This next part is where the true skill lies. You make a sudden movement that makes it look as though you've just thrown your glass at the ceiling. This will automatically make everyone in the room look up at where they think your glass is moving towards. As the upward motion begins, let your glass slip out of your hand and catch it under the table with your left hand and cover it immediately with your waiting napkin.
The whole action must be smooth, clean, quick and look natural.
As far as the next part of the trick goes, it just takes advantage of the momentary shock within the room. As you have the glass inside a napkin in your left hand under the table, put your right elbow on the table, lean over to the person on your right, and say something like
"Where did it go, did you see it?"
This provides a distraction and your right arm gives you cover. Then it's just a case of using your left hand to move your glass and napkin under your right arm and into their jacket. It's a good idea to make sure that their coat has a suitable place to hide your glass before you even attempt this trick. If not, start the trick by drinking with your left hand and hide the glass with the person to your left.
Once you've basked in the glory of the trick, slowly produce the glass from where you hid it and continue your drink.
One of the greatest strengths of this illusion is that it is totally unexpected. So make sure that you don't give any indication of what you're about to do. But as I mentioned, you should say something to draw attention to yourself before you start the trick. It's a fine balance that will develop with practice.
Too much attention and people may see through the trick, not enough attention and most of the people in the room will miss it, which is a pity as you can't do this trick more than once for the same set of people. Oh, and it doesn't have to be a wine glass, it can be anything that you drink from, such as a coffee cup or a glass of champagne. Just make sure that you can do the trick well before you risk your guest's best glasses.