Get down on the floor and grab the dumbbells hammer-style with your palms facing in. The dumbbells should be aligned right in front of you in line with your mid-chest and your arms slightly bent. This is your starting position.
Slowly roll the dumbbells outward to the sides and lower your body towards the floor. Then, squeeze the dumbbells back in to the original starting position. Do this movement for the desired number of repetitions.
Perform this exercise in a smooth and fluid motion
Lower your body until it's about 6 to 8 inches above the floor
Don't lock out your arms at the top
Don't let your chest touch the floor
Don't do this exercise if you are a beginner
SPECIAL NOTES & LEVEL of DIFFICULTY VARIATIONS
To increase the level of difficulty, slow down the movement.
This exercise is for advanced weightlifters only. It is hard to execute and will put a great number of other muscles to the test. That being said, when you get to a point where you can execute this movement, it will do wonders for your chest because it's so unique in how it "hits" your muscles. This exercise will help you break through a growth plateau in no time.
They key to remember is that the type of dumbbells you use for this exercise is very important. You will need dumbbells that can roll fairly smoothly. Rusty dumbbells, or dumbbells that are solid-state (cannot roll) will not work. Thus, there is a specific equipment requirement that needs to be met before you attempt this exercise.