Sit down on bench with dumbbells resting on lower thigh. Kick weights to shoulder and lie back. Position dumbbells to sides of chest with bent arm under each dumbbell.
Press dumbbells up with elbows to sides until arms are extended. Lower weight to sides of chest until slight stretch is felt in chest or shoulder. Repeat.
Dumbbells should follow slight arch pattern, above upper arm between elbow and chest at bottom, traveling inward over each shoulder at top. No need to drop weights - see suggested mount and dismount techniques: standard or advanced. Also see mount & dismount from special machine rack and Bench Press Analysis.