This drill is a regular 5 on 5 scrimmage. The difference is that a second smaller ball is used. In addition each player must have their own basketball, and maintain their dribble constantly during the scrimmage. No player can participate in the action of the scrimmage without their ball and dribble.
The game of 5 on 5 can be played to 3, 5, 7, 9, or 11 baskets.
What makes this drill different from a regular scrimmage is that you can only score with the smaller ball. The bigger ball is dribbled in opposite hand when you shoot. You can advance the small ball with the pass, but an offensive player can only advance the smaller ball if they have control of the dribble with the bigger ball in the hand opposite the small ball. The dribbler can exchange the dribbled ball and smaller ball to go left or right with the dribble or they can advance the smaller ball to a teammate by the pass.
If the player loses either their dribble with the big ball, or possession of the smaller ball they must immediately put the smaller ball on the floor, and it is a free ball for both teams. The same is true is the small ball is dropped during a pass or catch attempt.
Each player on the defending team must also be dribbling a basketball, however they can play aggressively to knock the smaller ball out of the hand of the offensive player or knock their regular basketball away.
This is the primary way for the defensive team to gain posssession, or by stealing the pass of the smaller ball. No large balls are ever passed, only dribbled. Again, you only score with the small ball.
Hand-Eye Dribble and Passing Coordination
10, each with a regular basketball.
1 small ball is also required.

The basketball drills are licensed under a Creative Commons License.
TLC: Pål Degerstrøm 2000-2008