If a cueball rolling naturally down the table without sidespin or slide strikes an object ball full in the face, the impact will stop it dead in its tracks for an instant--then the forward rotation of the cueball (which is reduced but not eliminated by the impact) will cause the cueball to move forward, "following" the object ball.
When striking the cueball with the cuetip, a hit half-way from the center to the top (actually 70% of the diameter from the bottom) on the vertical axis will cause the cueball to start with natural roll immediately, that is, with no slipping between the ball and the cloth. Hitting the cueball anywhere from that point to the center will create varying amounts of slipping between the cueball and the cloth until friction eliminates it and the ball is rolling naturally.
While it is possible to hit the cueball slightly higher than 70% of its diameter without miscuing, it is impossible to demonstrate in practice that doing so will create extra topspin. In other words, for all practical purposes it is impossible to strike a cueball so high that it begins its movement with more rotation than natural roll. The length of the follow after the cueball hits an object ball, then, (provided the 70% point is where the tip hits the cueball) depends only on how hard the cueball is struck.
As an aside, the term "force follow," is simply a follow shot struck hard. "Force follow" is not something different from a high-speed follow shot. Scientist George Onoda noticed an interesting fact about striped pool balls: the width of the stripe is exactly half the diameter. This permits an easy method of determining the ideal point to hit the cueball for maximum practical topspin. When practicing , use a striped ball as a cueball. Orient the stripe so that it is exactly horizontal. The top edge of the stripe is exactly half way from the center of the ball to the top, or 75% from the bottom! In practice, that's indistinguishable from the maximum striking point of 70%. Clean the striped ball, chalk your cue, and practice hitting the top edge of the stripe. After each try, examine the ball and see if the chalk mark left by the tip is on the edge of the stripe. You will soon learn that when hitting a ball high, it is only the bottom part of the tip that hits the cueball, which means that when addressing the ball with warm-up strokes, the axis of the cue is aimed above the top edge of the stripe.
There are several training cueballs on the market now that make it is easy to practice maximum spin shots. The one available from Elephant Balls has a red dot surrounded by a red circle with a diameter equal to the radius of the ball. Orient the red dot so that it is on the "equator" of the ball (one radius from the cloth) and the red circle marks the half-way point in every direction. (For free literature, phone Elephant Balls at 614/841-9390.)
What happens when you use maximum follow on a cut shot? On every cut shot, the cueball and the object ball depart along paths that are nearly at right angles to each other. A cueball with natural roll (no slipping against the cloth), which I define as maximum follow, leaves the object ball along the right-angle line, then bends forward in a parabolic curve. The position and nature of the curve depends on the speed of the ball. You can see diagrams of the paths on page 55 of Byrne's New Standard Book of Pool and Billiards (Harcourt Brace, 1998, paperback and hardcover) or traced in slow motion on Volume II of Byrne's Standard Video of Pool (Premiere Home Video, 1988).
Much of the artistry of the game depends on the ability to judge the cueball's curving path on follow and draw shots, both for maximum and less-than-maximum off-center hits.
If you have absorbed the foregoing, it will come as no surprise that maximum draw or backspin results from a hit that is half-way from the center of the cueball to its resting point on the cloth. Trying to hit lower than that greatly increases the chance of a miscue. If the bottom edge of the cuetip hits the cloth first, for example, a miscue is almost a certainty. The best way to find out what a maximum-low-hit looks and feels like is to use a striped ball as the cueball with the stripe horizontal. During your warm-up strokes, try to direct the upper edge of the tip at the low edge of the stripe, and after hitting the cueball, retrieve it and see where the chalk smudge is.
To further reduce your chances of miscuing on maximum draw shots, make sure that your tip is properly shaped and groomed and is well-chalked, your bridge snug, your cue is close to level, and your speed is proper for the distance the cueball has to travel to the object ball.
Players who have trouble getting lively draw action almost always aren't hitting the cueball low enough. The second most frequent flaw is not hitting the cueball hard enough when the cueball is more than a couple of feet away. Third is not having a properly chalked tip.
A final suggestion. To learn how to apply maximum sidespin, practice with a striped ball and orient the stripe vertically. The edges of the stripe are as far from the center that you can hit without miscuing.