If your post-pregnancy or - even worse - post-nursing boobs reduce you to tears....turn away from the mirror. We just need to do a little camouflage. Most post-preggo/nursing boobs can be supported with a good bra (even if it's strapless). So make sure you have a good strapless bra that fits. The problem then becomes the cleavage. It's the cleavage that gives away the sag. So avoid maxi dresses with deep v-necks (I know, I know - that rules out most of them) and try a couple of different options:
Halter Neck Maxi Dresses
A halter neck maxi, when worn with a good strapless bra will easily hide any sagging boob problems. Below left is Manambe Dress, $168 from anthropologie.com. It's silk, so not great for running around (but perfect for a wedding), it's pretty, and the shape is perfect. Look for one like this.
Below right is a yellow tie-dyed Grecian Goddess Maxi Dress, $61, from Boutiquetoyou.com. Notice how high the neck is - no saggy cleavage will peak out.
Strapless Maxi Dresses
If your saggy boobs are also relatively small, strapless is a great option. Just make sure you wear the strapless top high enough to hide the cleavage. And again, get a decent strapless bra.
Below left is the Cora Long Dress by Lauren Conrad, $229. The ruffle will further help to distract from any sagginess. Below right is the Strapless Burst Maxi Dress, $28, from forever21. The bright pattern will also camouflage any lumps or bumps that are hanging lower than they should.