I've tried all sorts of different underwear for tucking, and the first one I've really liked for both comfort and appearance is a men's "full seat" dance belt I got from Amazon, made for ballet dancers. It has a lot of padding to keep everything from chafing, it smooths out the shape so there's no definition, and it has a thick wasteband that keeps it from sliding down. It's kind of "puffy," so not ideal for tight pants, but you can't see it under a skirt. Even if you can see it, there aren't any discernible outlines visible.

Has anyone else here worn one before? It seems like a good option for certain outfits, but I haven't see it be recommended for transgender women much.

I can't say that I've tried it but I think this could work well in some situations. Thank you for sharing your experience!