If the chair is wide enough, like with an ottoman or loveseat, the person being penetrated can sit with their knees bent, in a half-kneeling position.
I also can't find any reviews on these sofas or any other news articles about them, and they don't respond to my emails.
All models on this website are 18 years or older.
This weightless bounce is a unique experience and one of the main reasons sex stools have become popular.