I have rounded shoulders (which is the main cause of straps slipping when you move your arms). Last year, I found this little plastic gadget online called "Embrace" that fits in the middle of the back straps, pulls them together back there a bit, and keeps the straps from falling down! I use it on two of my bras -- the rest of them don't do that, for some strange reason. Now, if they would just come up with something to keep the long purse straps from slipping down, I'd buy it in a minute. Here is the Internet site fro Embrace products:
www.iloveembrace.com
Hope that helps!
Moe
www.iloveembrace.com
Hope that helps!
Moe