ろりぱらセカンドストライク! ～あゆみの性態観察大作戦～

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]