I'm 158 cm tall and weigh 50 kg. I'm not very athletic, carry some weight around my midsection, and don't have very full hips or glutes. At Old Navy, I usually wear Petite XS in tops and Petite 4 in bottoms. I bought this swimdress in XS, but the built-in briefs feel completely disproportionate for ...an XS size, especially for someone who normally wears petite sizing. The crotch area is oddly long and poorly shaped, while the hip area is unusually wide. When worn, the back coverage is terrible — the sides flare outward instead of sitting flat against the body, so it doesn't properly cover the butt at all. For reference, I normally wear high-waisted, full-coverage briefs — the type people jokingly call "granny panties" — which already provide much more coverage than regular underwear. I've attached comparison photos for reference. The briefs shown are the Jockey Cotton Full Brief in size 5 and the Uniqlo Just Waist Briefs in size XS. Also, the crotch area is only single-layered and lacks any additional protective lining.