How do I stop my crack from showing when I sit?

When I wear jeans, my crack will show when I sit down. It doesn't matter what I do. If the jeans fit just right, my shows, if they're a little snug, my shows, if they're a little loose my still shows. I wear a belt and still my peaks out to say hello. Does anyone know how to stop this from happening? It's really embarring and I'm all out of ideas.