Perform the trick
Place your pitcher and glass on a table. Hide the plastic circle in the hand you won’t use to pour.
Pour water from the pitcher into the glass, until it begins to overflow. Say “I can tip this glass of water over my head and keep it from pouring out.”MM
Put down the pitcher and cover the mouth of the glass with the hand hiding the plastic circle. Secretly place the circle over the mouth of the glass, covering the entire top.
Pick up the glass with your other hand and turn it over quickly, but gently. Slowly remove the hand holding the top of the glass. If done right, the circle will stick to the glass and the water won’t spill out.
Lift the glass over your head and say “Magic tricks are hot work. I think I’ll cool off.” Then gently push on the tab. The plastic circle will come off and the water will fall on you!