Lie supine on bench with upper chest under bar. Grasp bar with wide oblique overhand grip. Disengage bar by rotating bar.
Lower weight to chest. Press bar until arms are extended. Repeat.
Orientation relative to lever will depend upon height of fulcrum relative to bench. Position body so bar is over shoulders during extension, yet lower on chest in lowest position. Range of motion will be compromised if grip is too wide. Also see Bench Press Analysis.