I could be wrong but that looks more like a strapon harness rather than a thong so the implied_futanari tag shouldn't apply here
I'm reverting these changes because according to several other posts, such as post #2713318, that's just what Unryuu's underwear looks like. I don't know if it's official, but there's enough examples of artists using that design that I'm reasonably confident that's what's being done here. Not to mention you can clearly see she's still wearing her skirt.