1:23 in this video
An old-school bodybuilding exercise that's great for developing that mind-muscle connection.
To perform this exercise properly, you truly have to be able to feel the muscles working.
Otherwise, you put yourself at high risk of sustaining an injury.
The starting position for the Fly looks very similar to the Dumbbell Neutral Bench Press.
The difference is when you're not going to lower the dumbbells straight down, but rather you will open your arms like you're getting ready to give someone a weird hug.
Keep the elbows bent throughout the whole movement and only lower as far as your body allows.
Once you reach your end range, you will reverse the motion and focus on using your chest to raise the dumbbells back up and together, squeezing at the top.