Sister, Sister, Sister is the story of a virginal male protagonist whose older identical twin sisters help him to lose his virginity. There are branching pathways, player choices, and multiple endings. Will you romance your own twin sister? Your mother? The girl from across the street. Or someone else entirely?
In order for you to be able to install this game, you need to enable (allow) installation of applications from unknown sources (Unknown sources) in the phone settings. Usually this item is in the Security section