Yesterday, I finally got myself to a high-quality lingerie store (Hush, in Brighton, MI) and had myself fitted for the correct size bra. I've been wearing a 32D since a sales woman at Victoria's secret informed me that that was my size a few years ago (before adding that they didn't carry that size. They do now, however). Before that, I crammed myself awkwardly into a 34C. But even going down a band size and up a cup size wasn't enough. I can't tell you how many times a day I shake my boobs back into the cups or hike up a strapless bra if I'm wearing one. After some digging online, I decided that this was one thing the Internet probably couldn't help me with. I was not going to be able to get sized remotely, buy bras I've never tried on, etc.
I walked into Hush a 32D, and I walked out a 30G (or F, if you're still counting DD as a cup size and not just going straight from D to E). I wore one of my two new bras today, and it was a dream. I realized how much I adjust myself on a regular basis when I found my hands straying to my bra and then dropping, having found nothing out of place. Makes me wonder whether strangers have noticed me jiggling my boobs back into place!
The woman who helped me out at Hush was amazing; she made me feel like she was really focused on getting the best bra for me, regardless of sales (when they didn't have a white strapless bra that fit me, she actually mentioned another store in another city that sells unusal sizes like mine, so that I might be able to find the perfect bra before my wedding...I ended up deciding on a nude strapless instead, and I don't think I'll ever go to another store for bras), and she offered to order bras in my size if they didn't have them in my size.
Anyway, if you've never been fitted for a bra at a small store (not Victoria's Secret...they're not actually allowed to touch you, so they can't really do an accurate fitting), you should. You might find yourself in a cup size that's 3 sizes different from what you're wearing!