For work I use a patterned shirt with stripes and an under shirt to be somewhat effective. When I wear solid color shirts and an under shirt I am more noticeable.
Yesterday I put the trash out, I was wearing a striped thin cotton pullover shirt (it was 50 degrees out) and when I came in my wife and daughter were sitting in the family room and my wife said, "it is cold out". I said why and she said your nipps are showing; also, you are bouncing around when you walk. So this summer will be interesting.
When I work out at the gym (LGBT gym and very safe) I wear a sports bra with individual cups from maiden form.
I am probably an A+ cup and need to get fitted very soon.