I was curious as well and found this video explanation[1]. The idea is that tapping on the back of the controller pushes it up into the player’s thumb which is

I was curious as well and found this video explanation[1]. The idea is that tapping on the back of the controller pushes it up into the player’s thumb which is resting on the D-pad causing a button press. [1] https://youtu.be/n-BZ5-Q48lE https://youtu.be/n-BZ5-Q48lE