Ive been layering a vest under tops to feed usually but...
I just ordered a bandeau/tube top to wear under other tops to bf without exposing my tummy! Cant be doing with flapping scarfs- dont mind getting the boob out its the belly i am conscious of. I just layer it under a top, pull the top up, tube down (like a vest). Works a dream! Much easier than a vest and means I can wear most of my favourite tops and t shirts even when BFIng (I hate most "nursing" tops).
Would never have occurred to me before as I don't do strapless EVER when not an under layer for feeding.
Had been advised about vests but a tube top works wonderfully. Also they're pretty cheap on ebay.