awwww I love these kinds of domestic fan-art. It's so heart warming and pure. My first BD ship was SayoTsugu and I don't regret it. Also, Tsugumi seems to be the kind and open-minded mommy and Sayo must be the strict but loving mama c:
Don't know if this is the stream they are talking about, but here Kiara confirms that in a hypothetical date she would be "quiet as hell" and Calli would have to take the lead https://youtu.be/3HCmVIQ-8zM?t=2960
Sounds like a Glass Cannon.