Get a peeled, hard-boiled egg, a bottle with a large opening (but not large enough for the egg to pass through) and a few matches. Apple juice bottles usually have large enough openings as do orange juice bottles. Soda bottles probably won't work.
Place the egg at the opening of the bottle. This is to show any spectators that the egg is too large to pass through it. Make sure people can get a close-up view of the egg and bottle so there can be no arguments.
Light two to three matches and allow them to burn for a moment. The more matches you use, the bigger the flame will be and the less chance the matches will extinguish.
Take the egg away from the bottle opening and drop the matches inside. Replace the egg immediately. Don't wait more than a couple of seconds to replace the egg or the trick may not work.
Watch as the egg gets sucked through the opening. As the matches extinguish the egg will get sucked through. The egg may jump up and down a bit but do not touch it.