A fun idea, but I wouldn't think that that would actually work. In the US at least, walls are at least thick enough to have two sides with space in the middle for wiring and insulation and whatnot. So, you'd essentially have to kick through two walls to have a hole to the other side - and you'd have to go to quite a lot of effort to get a hole that large. But it's not like hentai ever cared that much about reality, and maybe they make walls differently in Japan. Certainly, to have as much sound carry through as they tend to talk about happening in hentai implies that they're constructed differently. I've lived in places that had sound carry through before, but in my experience, in most places, it takes some pretty loud sound to get through the walls, which is not at all what seems to happen in many apartments in hentai.
...Well, that was a pretty interesting release.
From her suddenly appearing, telling him not to watch it, and then go from depreciating to suddenly pushing him down and the ensuing scene...Pretty unpredictable. I like it.
Great ending though. They may as well not bother fixing it, that way she can visit anytime.