In Japanese adult media, the scenario is a popular sub-genre. It creates a narrative of forced proximity. The tension arises from the need to be quiet or secretive while engaging in acts in a home that is not one's own.
To understand the meaning, we must deconstruct the sentence into its component parts: shinseki no ko o tomari da kara hentai
The particle is the most confusing part of the transcription. In standard Japanese: In Japanese adult media, the scenario is a popular sub-genre