Okay, this may sound a little weird, but give it a try...you might be small enough for it to work. I did it when I was very young, like 12, but then I grew too huge for it to be successful. You will need some wide hockey tape- preferably the old fashioned white cotton type. Lay down on the floor so your chest is flat. Rip about an 8 inch piece off the roll and stick it on the breast tissue near the outside. Pull it tight underneath your arm and stretch it around your back. Use as many pieces as you need to achieve the flattened look. This is really not a long term solution, but it did work for me on occasion when I was much younger and smaller. Do not use duct tape, or packing tape, but something that breathes like cotton.