Sit down on a flat bench with a pair of dumbbells resting on your thighs. Kick the dumbbells back using your knees and rock yourself down onto the bench.
The dumbbells should be even with your chest at the start of the movement with your palms facing away and forearms/upper arms forming a 90 degree angle.
With your feet, butt and shoulders firmly planted, press the weights up toward the ceiling in an arching motion until your arms are fully extended above you.
Lower the dumbbells back down until they are in line with your chest, and repeat.