Hang from the bar, with a pronated grip (palms facing forwards), hands about shoulder width apart, arms straight. Keep your legs together, core braced and glutes engaged.
Actively depresss your scapula, drive your shoulders down away from your ears. Maintain straight arms and start with a regular scapula pull up, then continue pulling, driving the chest up trying to keep the arms straight at the pull the torso toward a horizontal position.
Squeeze at the top, lower with control, allow the scapula to elevate fully at the bottom (cover your ears with your shoulders). Repeat for repetitions.