They're from a Mod, they're not Vanilla.
For Vanilla, there are "Lingerie Stockings" and "Paw Lingerie Stockings" that count as Sexy Clothing, or you can use anything that you make Jun wear and get a response from her saying something like "S-so... These are the sexy clothes..."
However, if you would like to use the mod, you must join our Discord Community Server, where you can download it. There are Instructions and everything from adding a Mod to making your own Mod.
Here's a link to join our "Discord Community Server" (Hope the link works.)
https://discord.com/invite/DNPZcSVK52?utm_source=mainmenu_mdrg_0.90.10&utm_mediu...
And here is "Fishnet Stockings Mod"
https://discord.com/channels/813853552400138261/970335900779294780/1325143281348...
https://discord.com/channels/813853552400138261/929160364594188329/1031690361443...