I do not suggest the black lace bra under a white shirt or a sheer shirt (god forbid the latter). No, nothing like that.
I tried a beige slip under this COOPERATIVE dress, and the look bored me. So I tried a back cotton knit slip instead, and was pleased with the contrast. I like the feminine pink, white, and lime green fabric, which has some sort of fruit pattern on it (I am undecided whether they are meant to be apples or cherries), against the flat back.