You would want to go with a boy shirt bottom or a longer skirt bottom. I say longer just becuse if it hits u right after your butt it will emphasize your thighs which you don’t want to do right? You could even get a cute cover up! I have just about the same problem that’s y.posted about 6 years ago
Swim skirts are cute if you like them! Boy shorts tend to make your legs look stocky so try a high cut bottom and see how it goes. The more fabric, the bigger your butt will look, it’s true!
If you’re wearing a two piece, you can go outrageous on the top and wear bright colours, ruffles, anything that will draw attention away from your butt/thighs.