Position yourself lying down on a barbell bench press and, using the same grip width you would use to perform the standard barbell bench press (a typical width to use creates a 90-degree angle in the exact middle of the repetition between the forearms and the upper arms), lift the bar off of the rack and hold it over your neck. Perform the exercise by slowly bringing the bar down until it is approximately one inch above your neck. After a brief pause in this position, press the bar back to its starting position by engaging your chest muscles. Repeat for the prescribed number of repetitions before placing the bar back onto the rack.
Ensure that the bar is directly above your neck at the bottom position of your exercise. If you allow the bar to drift forward, there would be nothing differentiating this exercise from the standard barbell bench press.