I started a thread about this 3 some years ago.
http://youlookfab.com/welookfa.....slide-down
It seems to happen with all body shapes!
I have a lot less slide than I used to and I think it's because I now:
-Almost always wear a belt. I love the basic belts from Madewell. My other source for belts are J Crew. The Madewell leather is good and it molds to your body in a comfortable way.
-Wear more loose fitting jeans than I used to, where slide is less likely to happen but a belt is even more essential to keep the pants in place. Of course this flies in the face of your Kut issue, which you sized up in to begin with.
- Wear a lot of cropped and ankle skinnies. I have a theory that, when wearing bootcut and longer stacked skinnies, the weight of the fabric as well as friction from walking pulls down the pants even more. I almost never get slide with shorts, even knee length shorts. So I think there might be something to my weight theory.
- Wear higher rises that stay up better to begin with.
- Let go of jeans that slide badly (if the belt doesn't fix it). I purged a pair as recently as a month ago.
A lot of jeans makers are now using better materials as well. They have their own names for it, Resolution, Stocking fit, Ultimate Fit etc. The two most recent fails were cheaper jeans (Kohls Vera Wang, and a pair of made-for-discount channel Paige Skylines I got at the Rack).
As you can see I have given a lot of thought to this issue as I wear jeans every single day, for leisure and for work. In spite of their flaws, jeans are still my #1 clothing choice and the basis of my wardrobe.
I suggest you wear a belt and just enjoy them until they truly drive you nuts. Then move on.