The ones you discreetly pull aside to reveal a hole to presumably pop a nipple through and nobody will be any the wiser. Think cheapo Purpless tops. I have to retrieve most of my boob through the hole in order for it to work, defeating the purpose really.
I usually do the vest under top approach, which is much more discreet for me. I have pretty large
saggy boobs with nipples perched rather far down so maybe this is why it works better than trying to fish my boobs into position through a hole. Is it just me who struggles or have I cocked up something as simple as wearing a top?