Step 2: Tape Tennis Balls Together
Lay the duck tape sticky side facing up. Place the two tennis balls on top of the tape a couple inches from the end. The balls should be touching and the tape should be right in-between.
First take the few inches of tape left on the end and wrap it around the junction where the balls meet. Press the tape towards the meeting point to close any gaps. Now roll the balls along the tape pressing in the tape towards the center as you go.