Ochiyuku Kyoushitsu

During school tour class visits toy factory and gets lost in its huge labyrinth-like basement. They are able to find food there, but food contains strong aphrodisiacs. Males together with the teacher start insulting the girls one by one. It all turns out to be a trap of a shady organization that transmits the whole breakout run online in the internet and its members bid on girls they like. Will main character be able to protect the girls or fall victim of this madness as well?

[From vndbreview]