Sit down on a decline bench with a pair of dumbbells resting on your thighs and with your legs securely hooked underneath the pads. The bench should be angled downward at roughly 30 degrees.
Carefully lay back on the bench while extending the dumbbells directly above you, palms facing in. With your butt and shoulders firmly planted and a slight bend in your arms, lower the dumbbells down in a circular motion until your upper arms are parallel to the floor.
Press the dumbbells back up following the same circular path until you feel a strong contraction in your pecs, and repeat.