Anonymous wrote:...problematic because the fabric is super thin, they have a single seam right down the crotch, and are very high/cinched waist while I am very long in the rise, so I’m wondering if the combo of all that causes the seam to obviously pull up my crotch in a way my others don’t.
This is a pretty solid explanation. No gusset = separation where you may or may not want it. The high waist on a long torso will also create this issue.
The fabric isn't something you can do much about, so your options are: adjust the waist so it doesn't pull up as much (i.e. roll it down), or adjust what you're putting against that single seam to change the shape. Super tight underwear might do it, but will likely create other problematic lines.
Pantyliner is a possible fix, but may actually exacerbate the issue if it also folds over that seam (or requires additional layers).
Fellow burlesque artists use these:
https://www.amazon.com/Cuchini-Camel-Keeping-Kardashians-Doctors/dp/B009SNB978