The bodysuit is well constructed and generally quite comfortable. While I've yet to find anything else as good, with a few refinements it could be amazing!
The cotton/elastic used for the thong portion is far too bulky and heavy. It would be infinitely more comfortable and flattering if it used a string-style back like the Cotton Rib T-String Thong instead. This would also allow for a single snap closure, which would minimize friction against the taint.
The leg cutouts either need to be lower cut like a brief, or much higher cut so they fully clear the hips. The current design means the cutouts awkwardly rise ever so slightly above the waist of pants/shorts, even when wearing a lower rise. It looks more ill-fitting than flattering. If the cutouts were lower, the bodysuit would be discrete and simply resemble a tucked undershirt, which is good. If the cutouts were substantially higher, the bodysuit would be much more flattering and flirty, which is also good. Just commit one way or the other!
I hope to see this refined version in the future.
