Fingers behind the ball

my sons fingers will not stay behind the ball,it acts like a slider,it goes from one side of the plate to the other,anyone know of any drills that might be helpful.

Draw a thick black line around a ball using a black magic marker. Have your son grip the ball such that his fingers align with the black line. Then have him throw the ball and try to keep the black line from spinning or wobbling.

Is he keeping his thumb under the ball. I seen several boys throw and the ball will spin clockwise if you are facing them. I noticed that some of them was placing thier thumb on the side of the ball. Also he could be angling his wrist to the outside. Roger’s suggestion is a great drill.

Great point. Make sure he grips the ball such that thumb and middle finger cut the ball in half.