Train the double pass on a fixed grid: a disciplined first set, an immediate second ball, and a turn out on the second rather than a forced turn on the first.
Mark a 20x20m square, one player and one cone per corner. Nobody moves off their corner. Pass to a neighbour along an edge. He sets it back first time without trying to turn. Play him the identical ball straight away, and this time he turns out and passes to the next corner round. That corner then works the same double pass with his own neighbour. After one lap, reverse the direction so the other two edges get the double pass and the walls turn the other way. Two touches maximum for everyone.
A square where the ball goes round one pass at a time trains striking and nothing else. Every receiver is square to the ball, nobody has to make a decision, and the exercise has no failure mode. Adding the double pass changes that with no change to the setup at all: the same four players on the same four cones now have to solve the most common problem in midfield, which is what to do when you receive and cannot turn.
The answer the double pass gives is that you set it and get it again. The defender who has leaned in to stop the turn has to reset when the ball goes backwards, and if the second pass arrives quickly enough it lands inside that gap. This is not a trick. It is the standard escape from a tight receive and it appears in every good side's build up several times a game.
What makes or breaks it is the interval between the set and the second pass. The window the set creates is roughly a second long. Take a touch, lift your head, then pass, and the ball arrives after the defender has recovered, which is worse than not setting at all because it has now been played into pressure twice.
The two passes in should be identical. Same weight, same line, ideally the same foot. A receiver who knows exactly what is coming can commit to a clean one touch set on the first ball, and the whole thing runs at the tempo it needs. Change the second ball and he has to solve a new problem on the one he was meant to attack.
Reversing the direction after a lap is what stops the same two players doing all the setting. On a square, the double pass only ever uses two of the four edges in a given direction, so the reverse lap is not a variation, it is the other half of the exercise.
Save it to your private drills, then change the animation, adjust positions, swap equipment, or drop it into a session block. Or start from a blank pitch and build your own.