No secrets to the setup here. Just place the balls next to each other inside the rack. Or start by jumping over smaller barriers first. You may find it easier with the balls frozen or with a small gap, so experiment a little. It gets harder when the balls start getting more than a ball width apart, but that's also when the real fun begins!

The hardest part is probably holding the cues. I cross them with the top one going outside. I've also seen it done just by holding the two cues side-by-side, but I couldn't get that to work for me. Try gripping at different points to see what balance works best for you.

To shoot the shot, steady both cues and get each tip in position. You'll only need to be back a few inches from the balls. Don't take a backswing; it will likely mess up your alignment. Lean in to it and stab the balls.