It depends on the size of the bra but for me, I use a long, button-down t-shirt with a slight pattern (i.e. plaid or vertical stripes). Basically, something to break up the light. I've almost been caught at work because I tried to wear a smooth, single-colored polo with a modest size bra. I convinced the guy it was part of my normal chest. Anything that has a large smooth (i.e. polo or regular t-shirt) or shiny will likely attract unwanted attention. I'm currently experimenting with various styles of shirts to see what I can get away with. My next experiment will be with single-colored button-down.