Lolipara Second Strike! ~Ayumi no Seitai Kansatsu Daisakusen~

Four people used big brother's room as their secret playground.
Once, the leader was the big brother, however now Ayumi is the one who takes control.
Ayumi's target for this time is Maina and Takuya, her junior fellows in school. Ayumi offers a room for them as a secret playground. And of course, the room is full of erotic toys!

[From English DLSite]