Ducking around and behind a skilled opponent develops your ability to see an opening and take it before the changing positions in a wrestling match make that opening disappear.
The takedown is a bread-and-butter move in wrestling, the way one wrestler takes his opponent to the ground and establishes control. Takedowns to the lower half of the body begin with a "shot": diving toward the opponent's legs to grab them. The faster your shot is, the more likely you are to capture the legs before your opponent can react with a countering move.
To begin a session of knee tag, two wrestlers stand facing one another as if beginning a regular match. When play begins, the wrestlers try to slap one another on the front, side or back of the knee. Each uses his hands and leg position to keep the other from scoring. This drill works on the basic speed of a shot: going for an opponent's legs as quickly as possible, without telegraphing your intent ahead of time.