Futarikiri 3 paku 4ka (Alone together - Four days and three nights)

I was supposed to relax all day at home in the parent's absence on the trip, but my elder sister suddenly quitted her job!!! I was never dreamed that we stayed at home alone together all day...... Adventure game with command selection. Sex scenes are described with animation.
Operational requirements:
DirectX 7 or later, and Windows Media Player 6.4 or later.