Back of the Ball aiming is a technique not a system.
Visualize two parallel lines on either side of the object ball to the center of the pocket. Then look for the center on the back of the object ball between these two lines that allows you to create a line of aim through the object ball to the pocket. This is the contact point that runs through the object ball plus 6 – 9 inches. I call it a nine inch nail that runs from about 1 1/4 inches behind the object ball through the object ball to the pocket. Continue to stare at this contact point and line of travel as you walk into and bend over the shot.
When you are in the shooting position and the contact point and line of travel are fixed in your mind, use the front dead center of the cue ball to strike the object ball contact point and move the object ball down a line that runs through the object ball plus 6 – 9 inches. This works for a straight in shot. The cue stick should travel down this line of aim from six inches behind the cue ball to six inches past the cue ball. It takes some effort and practice to learn where the front dead center of the cue ball is located.
Visualize the cue stick staying on line all the way to the object ball contact point. When there is a long distance between the cue ball and the object ball I will often create an intermediate target half way to the object ball that would be a dot or some others spot on the cloth used as a reference point that shows a straight line to the contact point. Do not move your body until after the cue ball strikes the object ball.
After you have learned where the front dead center is on the cue ball you can begin to learn where the front of the cue ball strikes the contact point for an off angle.
While we all make adjustments to set the stick on line it is important to recognize that you must have a perfectly still body when executing the shot. Like a marksman with a pistol. Place your weight on your heals, brace yourself, stop breathing and swing only your forearm from the elbow down.
Well that ought to get a rise out of somebody, that is one of the reasons I posted it. Later you can add various forms of cue ball control as needed. I would suggest reviewing Joe Tucker’s simultaneous use of front and back hand offsets for learning cue ball control. His videos are on the net Here is a place to start.
https://www.youtube.com/watch?v=GYsNj7EXaAA