huh, did not expect that to actually happened, but i am happy that the author have the guts to make the main characters did it. gotta wait another month to see if we get to see the extension of the whole scene or just plain continue from there.
judging how the first volume ends in chapter 5, most likely volume 2 will ends in chapter 10 with that cliffhanger. if volume 3 does start with chapter 11 and it's sex scene, hopefully there are more to come~