If you want to try an interesting variation that, for me at least, seems to work a lot better than a conventional flye, hold the dumbell with your hand right up against the last plate, and instead of having the palms facing 'up' through the movement, keep the thumb facing up instead, so that you're essentially holding the dumbell unevenly and keeping it pretty much vertical to the floor at the bottom stretch portion of the movement.
I've had good gains doing these instead of the normal way and the stretch seems to feel better too.