As a male, I'm going to share this information with you. Most kpop idols wear women's jeans and not jeans specifically targeted for men (because of how they fit) but because of this the in seam (the seam that goes between your legs ) is a lot higher up on girls jeans vs men's jeans. So even if they are not "big" in their flaccid state they will appear to be. This is because the in seam being high pushes your balls up against your dick and means they've to sit tightly together. Creating a bulge.