Hold up. Masaru got to touch Kazu's face AND his breast forms? I know that it's been hinted very strongly he knows his friend didn't really turn into a girl, but I guarantee you that breast forms don't feel like the real thing. Touching his face would've given the game away too, because unless you're doing kind of laser treatment you're not going to get rid of ALL the stubble.
inb4 it turns out Kazu really did turn into a girl and they're the one deluding themselves.