“Bolster” (commonly known as Aligner Chewie) is a small cylinder made of a soft spongy plastic-like material called Styrene Copolymer. It looks like a small roll of gauze or cotton.
“Bolster” helps to close any air gaps between your teeth and your 3D Aligners. Typically when you get a new set of 3D aligner trays, they may not fit tightly against your teeth at first. Biting on the “Bolster” helps 3D Aligner to fit tightly on your teeth.
Just position the “Bolster” between your teeth (keeping aligners on teeth) and bite on it. Quickly move it from one end of your mouth to another, continuing to bite up and down, until you have bitten on it with all of your teeth.