I need to make sure the response is helpful without any assumptions. Perhaps the user is referring to a specific game or a fan-made content involving these terms. However, some terms like "casting couch" can have adult connotations, but in a horror context, it might be part of the setting.
First, "backroom casting couch" might refer to a hidden or secret room, possibly in a horror or thriller context. The term "casting couch" could be a play on the phrase related to the entertainment industry, but combined with "backroom," it might suggest a hidden place involved in some illicit activity.
Then "Kayla Still" is likely the name of a character or a person. "In high install" is a bit unclear. It could mean a high installation of something, maybe a game or software? The user might be referring to a game or a media content where these elements are part of the narrative.
