This can best be accomplished by filling to the top edge of the glass and inserting the stoppers which causes the water to squirt from the tubing. When the stoppers are firmly in place, turn the container over and shake. Water will slowly come out of the tubing. Stop shaking when the water is at the desired level. The tubing can now be swabbed with a small cotton swab or pipe cleaner.
Bottles are now ready.
Place the equipment as shown in the photograph. Light the burner. Pointing the flame at the round flask, make a pass at the large area. Glass will expand and the water level in the tube recedes. Pass the flame at the narrow end of the whiskey bottle.