This phrase is sometimes linked to fan-favorite niche anime or manga snippets shared on platforms like TikTok and Facebook . Japanese Family Members Explained | Kazoku vs Shinseki
本記事では、親戚の子供（親戚の小＝「shinseki no ko」）とのお泊まり（お泊まり＝「o tomari」）を成功させるための準備、寝る場所、アクティビティ、そして注意点をまとめました。 shinseki no ko to o tomari dakara de na na
Or possibly it's from a specific anime, manga, or meme context. The "de nana" at the end might be a name (Nana), a number (7), or just a playful ending. This phrase is sometimes linked to fan-favorite niche