Bisection
The things you will need are:

1 pair of pants that matches the one you'll wear when you perform the effect.
1 piece of aluminum bar that's 1" wide and long enough to wrap around your
waist.
Black cardboard (enough to cover the area of your waist)
Black tape
Foam
Trench coat
Scissors

Building the gimmick:

Step 1. Cut the legs off of the pants right above the crotch. The pants should
now form a tube.
Step 2. Bend the aluminum bar around your waist. Remove the bar from your
waist and tape it where it overlapped forming a ring in the shape of your waist.
Step 3. Place the aluminum ring on the black cardboard. Trace the outline on the
cardboard.
Step 4. Cut the shape from the cardboard. Trim any edges that overlapping.
Step 5. Cut two blocks of foam from the sheet of foam. The blocks should be
approximately 3"x2"x1"
Step 6. Tape the blocks to the underside of the cardboard cutout.
Step 7: Place the ring on the inside of the pants. Open it up a bit more if it
doesn’t fit in tightly.
Step 8: Place the cardboard cutout on top of the ring a few centimeters below
the top of the pants.
Step 9: Tape the cardboard and ring to the inside of the pants.
Step 10: YOUR DONE!

Performing the effect.

Step 1: Begin with the gimmick hidden inside your jacket.
Step 2: While holding the gimmick with your right hand on the inside of
your jacket, use your left hand to spread the pants open.
Step 3: Bring the jacket and gimmick directly in front of your body.
Step 4: Rise the gimmick to eye level.
Step 5: Lean your head and uper body towards the gimmick and place it on
your head.
Step 6: Lower the jacket as you lean forward and then lower your hips
towards the ground.
Step 7: Bring your body to the squatting position. Use the jacket to
shield the movement of your legs.
Step 8: Lower the jacket to reveal your mising mid-section. Hold this
positnion for just a few seconds.
Step 9: Quickly stand up and bring your hands towards the gimmick.
Step 10: Drop the jacket and concealed gimmick to your side.

thank so much!!!