That happened in chapter 29, they're just making a call back to that scene. I don't know whats the song from this chapter, but I can bet a dollar it's from Sonic.
having a girl like funabori carrying a porn mag really is more important than an alien invasion, if anything corrupts her it could very much cause the end of the world :shamihuh:
I know he had the realization last chapter but this feel a little too sudden, he could've waited for her birthday at least. (but I hope he doesn't pussy out now)