This exercise is a great supplement for the bench press. It will hit all the weaker support muscles that go into the bench because there isn’t the bar there for balance. Choose a flat bench. Dead lift the dumbbells up off the floor, and rotate them to where one end is resting on your thigh. Now sit down while keeping the dumbbells in place. You should now be holding the dumbbells vertically, while resting them on your thighs. Now hug the weights to your chest and lean back on the bench, carrying them with you. As you go down shift the weights to your arm pits.
This is the start position. With the inner end of the dumbbells in your arm pits, press them up, bringing the ends together at the top. Return to the start position.
This exercise is great for building tricep strength as well as helping you push past a plate on your bench.