It doesn't seem to matter where I buy them from, I have always had the same problem.
In the shop, and after every fresh wash, my jeans sit perfectly against my body.
Within about 20/30 minutes they've slipped down around my hips, making them look too tight on me, and pop the pockets inside out a bit. They look fine again if I hoik them up to the start position, but it doesn't last long.
I've tried bigger jeans in case I'm wearing them too small, and they're ridiculously, obviously too big, so never hold up at all. I've also tried to downsize and it's not much different, only more obviously a muffin-top!
Please give me a solution someone!