So the phrase might mean something like: “Because I’m staying over at my relative’s child’s place.”
The keyword has gained significant traction on social media platforms, particularly in the form of short video edits and recommendations: shinseki-no-ko-to-o-tomari-da-kara.html
While the keyword can be a generic phrase, its specific ".html" or title format usually points toward a niche Japanese adult or semi-adult media property. It is best known for its "home-based" narrative and the specific relationship dynamic between the two main characters. So the phrase might mean something like: “Because
The phrase (親戚の子とお泊まりだから) translates to "Because I'm having a sleepover with my relative's child". While the literal meaning is innocent, it is widely recognized online as the title of a specific adult-oriented Japanese media series. shinseki-no-ko-to-o-tomari-da-kara.html