It's just that the part near the nipple is round, a bit like a woman, right, hehe! Then practice it into a square. When you press on the bench, you can expand the outer edge of the pectoral muscle by keeping the width of the pectoral muscle.

You can exercise the lower edge by doing reclining push and bending and stretching of parallel bars-but be careful not to exercise only the lower edge, otherwise the chest shape will still be ugly.

Then clamp the chest with a pulley device.

In this case, the lower edge is wider than the sharp circle.

If you are fat and have more fat, then of course you should lose fat. The recommended practice is to do strength exercise first, and then run aerobic exercise on the treadmill to consume excess fat.