kazuma and kugayama's mysterious abandoned school adventure

Kazuma (straight) is a big horror freak, so when his friend Kuga (gay) invites him on a test of courage in an old school, he follows along, but when they get there, Kuga says that every time Kazuma gets scared, he gets to do "something sexy"...!? It's not super scary and there's no game overs. Also it's only R15; there's no 18+ CGs, so don't expect that. [From https://boards.fireden.net/y/thread/2673197/]