So the question is...... Did they do it???

I think it's implied they did by the author's notes at the end. Apparently the extra shows the "adult" side of SouMegu. The author intended this for readers who only read the web version to be oblivious to this.

I think they've done it... the last panels where megumi was under soushi and then next panel was the blanket itself... ⁄(⁄ ⁄·⁄ω⁄·⁄ ⁄)⁄

Unless my eyes are playing me, I believe I saw a condom in their trashbin
⁄(⁄ ⁄·⁄ω⁄·⁄ ⁄)⁄