From the last update (0.3) between the teaser being put out, and the official release, it was 10 days. It was teased on Nov 2, and came out on Nov 12. If that holds true the release date could be the 9th. In reality who knows. Somewhere around the 9th is my best guess.
I've gone back and forth on this, between wanting it to come out and feeling a little upset that it's been a month and a half when the original plan was monthly updates, but I also want these updates to be good and high quality like they've been. Torimiata has already said this is going to be a bigger update as well, and that takes time. Let them cook and be patient because if it's as good as the first 2 updates it'll be amazing and worth the wait.
Edit: Also, as far as Terrace seeing Ayumi naked when she streaked, I don't think he saw anything. Everything major that has happened, we've seen. From Ayumi showing her breasts at the beach, to Terrace accidentally showing his penis, to Ayumi almost showing her breasts to Terrace. If it had been anything meaningful when she was streaking like him seeing her breasts or vag, I think we would've seen it. I think the most he saw was her ass as she ran by.
In terms of when we can expect sex, I'd say in a few more updates. This story is going faster than others I've played, and both the MC and Ayumi seem to be down with her being seen by other guys. I don't know how they feel about sharing yet, and that hasn't been established or even teased really, so that needs to be built up as well before anything significant like BJs or actual sex happens.
