Shinseki No Ko To O Tomari Dakara De Na Tum 2021 -

Translates to "because of an overnight stay" or "sleepover."

The phrasing "de na tum 2021" is an artifact of broken automated scraping, forum typos, or localized internet slang from South Asian or Southeast Asian anime communities. shinseki no ko to o tomari dakara de na tum 2021

This premise directly incorporates the elements from the keyword breakdown: Translates to "because of an overnight stay" or "sleepover