"A double hit is an illegal shot involving the tip of the cue stick coming into contact with the cue ball twice during the execution of a single shot. This foul may occur through double clutching the cue ball, or in situations where the cue ball is nearly frozen to the object ball or rail."
Most common reason on this site for double tapping, is when the (0) is close to the ball you are trying to pot. In various situations you can avoid the double tap though. Avoid shooting straight on the ball you want to pot. If you get an angle, you can work around it. The angle however depends on how far (0) is from the ball.
If there is more, or if I've said anything wrong, please do correct me. I dont play with the rules, since the only benefit from doing so, is keeping accidental flukes from taking place. Everything else about it is just annoying.
