I think they like to show it, as they flex their hips and bulge out in front. I think they enjoy the feeling of being young and healthy and being desired. They are also aware of the fact that it turns on some women and kind of flaunt it. I have noticed that the younger the swimmer, the bigger and more prominent the bulge. The older ones seem to be more comfortable wearing speedos, and don’t really care if you see it. Maybe it’s that they are older, and are not into showing off, or maybe they are “packing” less.