The Solution is Low Expectations: low back bra converters.
Put the sexy back in sexy back! Low Expectations low back strap hooks onto your existing bra to pull down the back strap, allowing you to wear plunging back styles while still having the support and discretion your normal bra affords. Low Expectations bra converters lower your bra band by an average of 5 inches, so it is a good option for scoop back dresses- especially for women who have more than the backless adhesive bras can handle. Keep in mind, however, that this isn't going to help with completely backless clothes.
How to Use Bra Converters & Low Back Bra Converters:
1) Loosen your bra straps all the way.
2) Hook the hook part of Low Expectations onto the eye part of your bra and the hook part of your bra onto the eye part of Low Expectations.
3) Wrap the strap around your stomach and connect the hook and eye.
Contains: 1 two-part strap
Color: Beige or Black
Size: Small/Medium (bra size 28-36) or Large/XL (bra size 36-42) (err on the larger side since you can adjust it down)
Material: Nylon elastic
Small/Medium measures 34.5 x 7 x 0.04 inch (88 x 17 x .1 cm)
Large/XL measures 43 x 7 x 0.04 inch (109 x 17 x .1 cm)
Made in China