So I signed up just to post here! I was googling for solutions to "my jeans won't stay up!" and found this post! haha!! I have a butt and fill out my jeans, but some of them still manage to fall, and I often wonder if the problem would go away if I had a slightly larger rear!
Recently, I've looked into exercises for the um...backside, and I discovered that it's important to focus on the gluteus maximus muscles. If these aren't developed, the gluteus medius muscles can overcompensate by getting larger (and this can actually look like love handles in the back!!). Much of the advice out there ignores this. I found this article really informative on what the best exercises are for women who are looking to develop a better shape back there. I'm hoping to be disciplined enough soon to start doing them myself! haha
I'm not yet able to post links, so just google "Secrets to Glamorous Glutes!" by Diane Fields and Richard Baldwin.
Edit: The "plie" is also a great exercise for focusing in on the gluteus maximus.