bra enhancers
Are you going to wear that strapless low back gown?
So what are you going to wear underneath it?

Enhancers strapless bra
Vera Wang has styled this strapless bra with molded, seam free cups, firmly padded with a layer of foam and supported by concealed underwiring. Complete with clear, detachable straps, it has a two hook rear fastening and a small bow in the center.
Commando Takeouts ® Silicone Gel Breast Enhancers Accessory
Set of 2 breast enhancers ("cutlets").
Are you going to go braless and let your assets sag?
Get a pair of bra enhancers instead. These not only support your breasts, they boost your cleavage as well. No bra straps required as you stick them on. You can wear them under that strapless low back dress confidently.