Room For Two

Well whatever is the truth there’s no turning back for those two!

Schrödinger's incest.

I remember there another manga with the same concept I wish I can remember the title it had sequel chapters

On the one hand, our sibling duo by the close might be seeking to put up a front to convinve the parents that they don't look at each other "... in that way".

Alternately, the parents "know" what's going down, but for now they choose not to raise the issue at this moment.

"Hey, Whatever Works!"