You need to know how to use the Poser Morphing Tool for most of Lunas sitting poses. Most of the baby poses
will cause very crumpled folds in the crotch area of the bathing suit. There is no way to avoid that.
So to get smooth folds you need to use the morphing brush which you will find in the Poser editing
tools (the small hand).
If you switch your "Document Display Style" to "smooth lined" or to "textured lined" it's easy
to see where the mesh needs smoothing or other adjustment.
For all sitting, crawling and similar poses, I would suggest to use the bathing suit with constrained
legs to make sure the hip part of the suit stays in place. For standing poses you may try which
bathing suit works better and more realistic for your needs.