We’ve already had an exercise in tactile/spatial imagination in the explanation for that section on imagination. Instead of a simple ping pong ball, use a ball with a more complex design. A cricket ball would be ideal, or a baseball for American readers. Failing either of those two, there are few people who don’t have a golf ball or two lying around the house. As always, begin with the breathing exercise, followed by acclimatising yourself to those stimuli around you which may prove distracting. Attain the blank-mind state, and you’re ready to begin.
As with the visualisation exercise, start by thoroughly examining the ball. Cricket- and baseballs have rather complex patterns of stitches, and golfballs have equally complex dimple patterns. Observe with both eyes and fingers, and set the ball aside. With your experience in using the preceding exercises, this will be much easier than your initial attempt with the ping pong ball. Once you can imagine the ball in your hand, imagine it as floating above your hand, and move on to other parts of the room, and then the house.