Specifically, “Gomu o tsukete to iimashita yo ne” is the (or the one-shot) of Long Story , and “01 web upd” means the first chapter was updated on the author’s web publication platform (e.g., Pixiv, Fantia, or a personal site).
If you want to read this specific chapter, here are the most likely places (note: availability changes rapidly for fan works): gomu o tsukete to iimashita yo ne 01 web upd
If you’re looking for:
The story follows a character named Nanami, the sister of another character, Mamori. After an encounter involving specific sexual instructions that are ignored, the narrative focuses on the consequences and subsequent sexual interactions. Specifically, “Gomu o tsukete to iimashita yo ne”
You can find production details and episode summaries on the TMDB page for the series. You can find production details and episode summaries
To give you the long story short (pun not intended):