Hold dumbbells (palms in) and lie on bench in good body alignment (abs tight, chest up, back straight) with feet in comfortable position. Position arms perpendicular to the floor. In a controlled motion, keeping upper arms perpendicular to the floor, bend elbows to lower dumbbells until forearms are approximately parallel to the floor. While maintaining the controlled motion, return dumbbells to starting position. Contract triceps fully, without compromising form. Do not allow muscle to relax before next repetition.
Here are a few suggested alternative exercises:Ball Band French CurlBall Band Triceps KickBackBand KickBacksBand Overhead ExtensionBand Tricep ExtensionClose Grip Bench Press - BarbellClose Grip Dumbbell PressDecline Dumbbell Close GripTricep Extension - Hammer Strength