"UP-D" often refers to threads on Japanese message boards like 2channel (now 5channel) or "Kichiku" (malicious/crazy) story archives.

Essay “Gomu o tsukete to iimashita yo ne” – An Exploration of Language, Culture, and the Politics of Protection

Example:

If you want to find more specifics about this series, tell me:

Do not delete text messages, chat logs, or voice notes. If the perpetrator texts an apology acknowledging they did it (e.g., "I'm sorry, I should have listened when you told me to put it on" ), this serves as critical documentation of a consent violation.