) Not a mod, but undressing isn't inherently sexual, and she could just just as well be dressing up too.
The panty portion is such a tiny sliver and so shadowed that it could be a featureless shade, and of you're zoomed in close enough to tell the detail, the sexualising focus is in your action and not the picture.
[@Meanlucario](/forums/tagging/topics/general-tag-discussion?post_id=4961044#post_4961044) I would say "translucent clothing", but hell if I can ever remember what the tag is actually called. All I remember is a long term frustration at technically incorrect and/or imprecise wording.