How to Handle a Sleepover at a Relative’s Child’s House: Etiquette, Preparation & Communication Tips
However, to be helpful, I can offer two alternatives: If you were trying to write about: "I’m staying over at my relative’s child’s place, so [something about an update]" — a possible corrected phrase might be: Shinseki no ko no ie ni tomari da kara, mal (mail/message) o upd(shita) (親戚の子の家に泊まりだから、メールをアップデートした) In that case, a long article could cover: shinseki no ko to o tomari da kara mal upd