If you look at the Eject button on the cover you just removed you will see that on the back side of the button is a metal plate.

This plate transfers capacitance to a circuit board on the PS4. You will see it ends with a little curled piece.

If you look at the PS4, where the curled piece would meet the PS4 (were it attached) there is a little square pad (like 4mmx4mm) on a circuit board.

This square pad is what we need to cover with a little piece of electrical tape to insulate the transfer of capacitance from the metal plate and disable the button.

Cut a little square of electrical tape and cover the square pad with it.